The scream outside cut off hard enough to leave the hallway feeling hollow.
Han Taejin kept both hands on the metal stool and stood very still.
The prep room suddenly felt smaller than it had a minute ago. The hum of the fluorescent lights, the faint hiss of the air vent above the sink, the weight of the interface in front of his eyes—everything had sharpened.
Voices slammed into each other outside.
"Move!"
"Get back!"
"Don't touch him—"
Something heavy hit the floor again.
Then running feet.
Not organized. Not headed in one direction. Just panic finally losing the argument.
Taejin stepped to the side of the door and looked through the wired-glass pane.
The corridor beyond the intersection had broken apart. Students were shoving past each other now, some trying to get away from whatever was on the floor, others still frozen in place because their brains had not caught up with the fact that freezing in place was also a choice. A professor had backed into the wall and was yelling at everybody to stay calm in a voice already wrecked by fear.
It wasn't working.
It had never been going to work.
The student on the floor was still half-hidden by the crowd, but Taejin could see enough.
The guy was no longer trying to get up like a sick person.
His shoulders were hunched too high. One arm jerked under him at the wrong angle, fingers clawing at the tile. His whole body moved with short, violent spasms, like something inside him had stopped caring what human movement was supposed to look like.
Two people were still too close.
One of them, a girl in a pale yellow cardigan, had both hands over her mouth and wasn't moving at all. The other, some guy with a backpack still hanging off one shoulder, looked like he wanted to help and couldn't decide how.
Bad instincts.
The professor took one step forward.
"Everybody back away!"
The thing on the floor moved.
Not a lunge yet. Just a sudden, ugly snap of motion that sent a fresh wave of screaming through the corridor. The guy with the backpack stumbled back so hard he hit the wall. The girl in the cardigan finally moved too—straight into someone else, which started another surge of bodies in the hall.
Taejin stepped away from the door before the wave could reach his room.
He set the stool down soundlessly and looked at the prep table he'd left closest to the entrance.
The rule had just become simple.
The room stayed closed. The hallway was dead.
He shoved the metal prep table against the door, angling it so the frame would catch the leg first if someone tried to force it open. It wasn't a perfect barricade, but it would buy him a little time. Maybe half a minute. Maybe less if the person outside was desperate enough.
The interface flashed again.
[Assimilation active]
[High-risk instability expanding]
"Yeah," Taejin said under his breath. "I noticed."
A fist hammered the door.
Not the handle. The door itself.
"Open up!"
A male voice. Young. Breathless.
Then another voice, farther back in the hall: "He bit her—he bit her!"
The first voice hit the door again. "Open the damn door!"
Taejin stayed where he was.
The pounding got harder.
"Please!"
Something scraped against the metal outside, maybe a body hitting the wall, maybe someone trying to pull another person away. More feet thundered past the prep room. The whole wing had turned into noise and bad decisions.
The voice on the other side dropped to a panicked half-shout. "Please, I'm not bitten, just open—"
A second voice cut across his. "Stop wasting time! Run!"
Then a wet, choking noise came from farther down the hall.
The boy outside the door cursed and bolted. Taejin heard his shoes skid on the tile as he ran.
Silence didn't come after that.
It got worse.
The first crash of real impact sounded like a cart being knocked over. Then another scream. Then the unmistakable ugly chorus of too many people seeing something impossible all at once and trying to explain it with the wrong words.
He moved back to the wired-glass pane.
The hall had opened up a little because so many people had fled. That gave him a clear view of the intersection for half a second.
The professor was down.
Not dead. Not yet. She was on one knee, one hand braced on the tile, the other trying to push something away from her. A male student had his mouth buried against her forearm.
Even from this angle, Taejin could tell it wasn't a normal bite.
The violence of it was wrong. Too fast. Too committed. The way the body moved on top of her had nothing to do with hesitation or confusion. It was all appetite and broken instinct.
A boy darted forward with a fire extinguisher and swung wildly. He missed once, hit the wall, then clipped the student across the shoulder on the second try. The thing on the professor jerked sideways, looked up, and Taejin finally saw its face clearly.
Dead eyes.
Not literally dead. Just empty in the way that mattered.
The expression on that student's face was not pain, panic, or shock. There was no person left in it. No delay. No confusion. Nothing trying to make sense of the room around him.
The fire extinguisher boy froze for one fatal second.
The thing on the floor launched itself up.
Taejin stepped away from the window immediately.
He didn't need to watch the rest.
The sound told him enough.
The extinguisher clanged onto the tile. The boy screamed once. Then the screaming turned into full corridor collapse—running, crashing, people shouting names, doors slamming one after another as whoever had made it to side rooms tried to shut the world out.
A second later, someone hit Taejin's door hard enough to shake the prep table.
Not knocking.
A body.
Then another impact.
He grabbed the stool again.
The third hit rattled the frame and sent the bottles under the sink clinking softly against one another.
"Shit."
He backed up one step, eyes on the door.
The handle twisted.
Stopped.
Twisted again, harder.
Not with the wild force of mindless attack. This was someone trying the room deliberately.
A girl sobbed from the other side. "Please let me in."
The handle jerked once more.
Taejin said nothing.
Not because he enjoyed it. Because he couldn't tell what was out there anymore. One panicked student? Three? Someone bitten? Someone already changing? The hallway had gone past the point where good intentions mattered.
The sobbing turned to ragged breathing.
Then the girl whispered, "Please."
A louder voice behind her shouted, "Move!"
A man slammed into something in the hall. Another scream cut across the first one. The girl at the door gave up and ran.
Good.
Or maybe not good. Just not his problem yet.
The impacts moved away down the hall. Then came the sound of one of the locked lab doors finally giving under repeated force. Glass shattered. Somebody shouted in victory like that meant anything. More feet pounded through the opening a second later.
Taejin lowered the stool a few inches and forced himself to think.
Staying in this room had made sense before the prep wing turned into a funnel for terrified people. Now the whole floor was unstable. Maybe the stairwell was still clear. Maybe not. If he waited too long, he'd lose the option either way.
His phone buzzed.
He stared at it for half a second before pulling it out.
Minwoo.
I saw one attack somebody This is real I'm in a classroom now
Taejin typed back fast.
Lock it. Push desks against the door. Stay away from anyone hurt.
The reply came after three long seconds.
There are 9 of us I think one guy got scratched
Taejin's jaw tightened.
He typed:
Then he shouldn't be in the room.
The answer came back almost immediately.
You serious?
Taejin looked toward the door as another crash echoed from somewhere deeper in the building.
Yes. Decide fast.
No response after that.
He hated that too.
Not because he expected Minwoo to listen. Because he already knew what most people would do with that kind of decision. They'd argue. They'd hesitate. They'd call it cruel. Then they'd wait until the decision got made for them in the worst possible way.
The interface pulsed at the edge of his vision.
[Local failure rate increasing]
[Corruption spread risk elevated]
That answered one useful question.
Spread.
So whatever this was, contact mattered.
Blood probably did too.
The pressure in his arms came back, stronger than before.
Taejin swore quietly and braced one hand against the sink.
This time the sensation didn't roll through him and pass. It lingered. Heat moved under the skin of both forearms, then down into his hands. His pulse kicked harder, then faster. A tremor ran through his right hand and vanished so quickly he almost thought he imagined it.
His breath felt shallow.
No panic, he told himself. Not because the interface said so. Because panic made your body stupid even before something supernatural got involved.
He took one slow breath. Then another.
The heat under his skin eased a fraction.
Not enough.
He looked down at his forearm.
Still nothing obvious. No black veins. No wounds. No discoloration.
That should have been reassuring.
It wasn't.
Something hit the door again.
Taejin grabbed the stool and moved sideways just as the prep table screeched across the tile a few inches.
That wasn't a panicked student.
Too strong. Too direct. The impact had landed high, near the middle of the door, not low like someone falling into it by accident.
The handle rattled once.
Then again.
Then the whole door shook under a violent slam.
He went very still.
A mindless infected—if that was what the corridor was filling with—should have moved on unless it heard or smelled something. Unless it had followed someone to the door. Unless the room itself had become the nearest obstacle in its path.
Another hit.
The upper frame groaned.
The stool felt heavier in his hands than it had a minute ago.
He backed toward the side of the room that kept him out of direct line with the entrance and listened.
No human voice outside now.
Just that impact. A pause. Then another impact. Not rhythmic. Not smart. But focused enough to be a real problem if it kept up.
Taejin's eyes moved over the room quickly.
Sink. Counter. Upper cabinets. Water. Broken glass if he needed it. The back service hatch still locked.
The stool was no good for holding the door forever. The reagent bottle was clumsy. The box cutter was small. The forceps were better than nothing.
He put the stool down, picked up the box cutter with his right hand and the heavier metal forceps with his left, then immediately switched them because his right hand still felt strange.
The door slammed again.
The prep table jerked backward another inch.
He exhaled once.
If the barricade went, he'd have to commit immediately. No hesitation, no seeing what the thing looked like up close and hoping it somehow wasn't that bad.
The next hit came with a wet sound against the door, as though something had struck it face-first.
Then silence.
Taejin waited.
Nothing.
He waited another three seconds.
Still nothing.
Either it had wandered off, or it was listening.
He hated not knowing which.
The corridor beyond the room had gone quieter overall, but only in patches. Distantly, he could still hear scattered screams and the kind of continuous, directionless noise that came from a building full of people trying not to die without any agreement on how.
One of the upper lights in the prep room gave out with a soft pop.
The room dimmed.
The interface remained perfectly bright.
[Host condition unstable]
[Recommendation: secure environment and minimize stress load]
"Then stop making recommendations and start being useful."
The interface, being a useless floating lie detector for the end of the world, did not answer.
His phone buzzed again.
Unknown number.
He stared at it, then answered.
"Hello?"
The line was full of breath and background noise. Then a voice he recognized from class, though it took him a second to place.
"Han? Han, is that you?"
Choi Daeun. Intermediate macroeconomics. Sat two rows behind him. Talked too much before class and never during it.
"It's me."
"Where are you?" Her voice cracked. "What's happening?"
Taejin looked at the door, then at the timer.
[00:06:11]
"I'm in the pharmacy wing."
There was a slam on her end of the call. Someone shouting. Then Daeun again, lower now. "We locked ourselves in a seminar room but one girl's bleeding from the mouth. She says it's just stress. Do you think it's—"
"Yes."
The word came out flat enough to silence her for half a second.
Then: "What?"
"If somebody's already bleeding and acting wrong, don't wait."
"You can't be serious."
Taejin closed his eyes once, briefly. Same conversation. Different voice.
"Listen to me. If you're going to throw her out, do it before it gets worse. If you're not going to throw her out, leave now."
Daeun made a noise halfway between a laugh and a gasp. "You sound insane."
"Maybe. But if I'm right and you wait, you'll be insane too."
For a second he thought she might hang up on him.
Instead she whispered, "There are twelve of us in here."
Bad number. Bad room, probably. Bad odds.
"That's too many."
"Where should we go?"
Taejin looked at the prep room door again as if it might offer a sarcastic answer.
"Smaller room. Fewer people. Water if you can. Stay away from anyone bleeding or convulsing. Don't let anyone make you wait for a vote."
A burst of shouting tore through the line so sharply he jerked the phone away from his ear.
Then Daeun said, in a voice suddenly thin with real fear, "She just bit Minji."
The call cut out.
Taejin stood there with the dead line in his hand for half a second, then put the phone away.
That settled one more thing.
It was spreading fast. Room fast.
Not hours. Not later tonight. Now.
The prep room wasn't safe. It was just less exposed than the hall. If he stayed until the whole floor filled with whatever the first one had become, he'd lose mobility, information, and probably the stairwell too.
Another slam hit the building somewhere below him.
Not a door this time. Bigger.
Maybe the main entrance giving under a rush. Maybe a barricade. Maybe just more people being idiots with furniture.
His forearm flared with heat again.
Worse.
Taejin looked down as the skin over his wrist tightened painfully for two seconds, then loosened. A pulse beat hard enough to see.
"Come on," he said to himself.
He needed to move before his own body turned into another variable.
He shoved the water and supplies deeper into his bag, clipped the box cutter onto his pocket for faster access, and dragged the prep table back from the door just enough to open a narrow gap.
Then he stopped.
Listened.
Nothing right outside.
No breathing. No dragging. No crying.
The corridor could still be full ten feet away. He wouldn't know until the door moved.
The timer dropped again.
[00:04:38]
Too late for hesitation.
He took hold of the handle, eased the door open an inch, then three.
The corridor beyond was empty.
Not safe. Just empty.
There was blood on the far wall near the intersection. A smeared handprint lower down. One overturned cart. Broken glass glittering under the bad fluorescent light. A backpack lay abandoned near the corner like somebody had dropped it in the middle of deciding what mattered.
No bodies visible.
No people either.
Taejin stepped out, pulled the door shut behind him, and did not bother locking it again.
The prep wing smelled different now.
Still disinfectant, still dust and stale air, but beneath it was a hot copper smell that made the back of his throat tighten. Blood. Not close enough to pinpoint yet, but close enough that he noticed immediately.
His own body noticed too.
The heat in his arms sharpened. His pulse jumped. For half a second, absurdly, he became aware of the blood moving under his own skin like it was something separate from him.
He set his jaw and started toward the stairwell.
Slow enough to listen. Fast enough to matter.
At the intersection, he looked once toward the main corridor.
The professor was gone.
The student with the fire extinguisher was gone too.
A dark streak marked the floor where something heavy had been dragged or had crawled. One shoe lay on its side a few feet away, still tied.
Taejin looked at it for half a second, then kept moving.
He was four steps from the stairwell door when someone burst out of the side hall and almost ran straight into him.
A girl.
Shorter than him, lab goggles hanging around her neck, one sleeve ripped at the cuff. She froze so hard her whole body locked.
He recognized her a second later.
The pharmacy student with the crate from before.
She recognized him too. Her eyes flicked to the stairwell, then past him, then back again. "You're still alive."
"Apparently."
A thud sounded behind her from the side hall.
She flinched.
"Was that one of them?" Taejin asked.
Her throat worked once before she answered. "I don't know what to call them."
"Doesn't matter. Was it?"
She nodded.
"More than one?"
"I only saw one. There could be more."
Another impact from the side hall. Closer.
The girl swallowed. "I was trying to get to the supply room."
"Bad timing."
"That's a little obvious right now."
Good, he thought. Still functional.
"Can you run?"
She gave him a look that suggested she wanted to say something rude and had chosen survival over style. "Yes."
"Then get in the stairwell."
A third impact came from behind her, followed by the scrape of something hitting lockers or metal shelving.
She didn't argue.
Good again.
Taejin yanked the stairwell door open and shoved her through first. Then he stepped back once, just long enough to see what came around the corner.
A male student in a torn varsity jacket.
Or something that had been one.
His head was tipped slightly to one side, jaw red, one shoe missing. There was blood across the front of his shirt and more on both hands, and none of it looked like it had dried long enough to belong there comfortably. When he saw them, his whole body changed direction without hesitation.
No fear. No confusion. Just movement.
Fast.
Taejin swung the stairwell door shut in its face and threw his weight against it as the thing slammed into the other side.
The impact jarred up both arms.
The girl inside the stairwell backed down one step so fast she almost tripped.
"Move," he said.
She moved.
He shoved the door fully closed, dropped the heavy bar into place, and listened to the thing hit it twice more from the other side.
The metal held.
For now.
The girl was breathing hard on the landing below, one hand against the rail.
Taejin's own pulse was hammering now, from adrenaline, from the thing outside, from the pressure in his body that still refused to settle.
The interface hovered in front of both of them.
[Assimilation begins in 00:02:19]
The girl looked up at the same line, then back at him.
"Do you have a plan?"
Taejin listened to the impact on the other side of the stairwell door, then to the distant noise from somewhere below.
He didn't.
Not a good one.
But standing still had officially stopped qualifying as a plan five minutes ago.
He looked down the concrete stairwell, into the dim emergency lighting and the lower floors where the building was about to get even worse.
Then he said, "We're going down."