Tuesday came five days later. He used the window.
Not the delivery window — not yet. The blind spot. 1843 to 1851, northeast corner, overhead light at maximum cycle. Eight minutes.
He had decided to use it for reconnaissance only. The decision had been made the way he made decisions now: not as a discrete moment of choice but as the outcome of a calculation that had completed, the way the Fate mark had arrived — quietly, because everything before it had been pointing here.
He waited in the common room until 1840. The other subjects were in their standard configurations. Tessaly was reading. Preet was absent — Preet had been absent from the common room for three evenings, which he had filed as: Preet is managing something, and the management requires his attention at evening hours when he would normally be here.
At 1841 he rose and walked to the east corridor at the normal pace of a subject heading to the bathroom. He turned north rather than east at the split. The overhead light was at maximum cycle. He walked to the northeast corner and stopped and stood in the blind spot and looked at the observation deck door.
He had eight minutes. He spent forty seconds on orientation — door handle, hinges, lock mechanism — and then he moved.
The corridor beyond the observation deck connected, via a secondary stairwell, to Floor Three. He confirmed it now: stairwell, Floor Three access, researchers' corridor rather than the subject-access corridor.
The researchers' corridor at 1842 on a Tuesday was sparsely occupied. Two doors with light under them — working late, both the kind of warm incandescent light that meant personal lamp rather than overhead, which meant comfortable, not procedural. Neither door was close to the stairwell.
He continued up the secondary stairwell to Floor Two.
Floor Two at this hour: quieter than during work hours, not empty. One researcher crossing the corridor in the far section, not looking in his direction. A light under the door of the main research suite. The supply office that Orra had described was two rooms along from the secondary stairwell — small, filing-heavy, the kind of administrative support room that would not be occupied in the evening.
It was not occupied. He opened the door and stepped inside and closed it behind him.
The delivery schedule was on a clipboard on the left wall. He looked at it for twelve seconds. Tuesday and Friday evenings, as Orra said. Current week: Tuesday delivery completed at 1730. Next: Friday, 1800 estimated arrival, window approximately forty minutes. The schedule showed two people on the surface-side receiving team. Regular staff, not security.
He looked around the supply office. Filing cabinets, two standard, no locks. He opened the left one. Medical supply invoices, equipment manifests, chemical compound orders.
The right cabinet was locked. He looked at the lock — standard pin tumbler, the same mechanism as the standard Floor Four room locks, which he had learned to open by feel at age thirteen out of operational curiosity. He opened it in approximately twenty seconds.
Inside: administrative personnel files, thin, two-page summaries. He found the section for security and operations staff. Four names, four roles. The security staffing for floor-level access: two overnight personnel, rotation schedule, shift changes at 2200. Current overnight staff: scheduled from 2200 to 0600, floors One and Two only. Floor Zero — the administrative entry level, ground floor — had a separate staffing notation: one during delivery windows, zero at other times except Tuesdays and Fridays when delivery overlap ran until 1930.
He reclosed the cabinet. He looked at the time by the supply office's wall clock: 1848. Two minutes remaining.
He left the supply office and walked back up the secondary stairwell. Floor Three passage, northeast corner corridor, observation deck blind spot, into the main corridor at 1851 exactly.
He walked to the bathroom. He was there for ninety seconds. He returned to the common room.
Tessaly was still reading. Orra was at the window. Nobody had noted his absence in any visible way.
He sat down and ran what he had learned against the working plan. Tuesday and Friday windows, forty minutes each, surface-side exit propped, zero security on Floor Zero during non-delivery evenings. The delivery window he could use was Friday. Not this Friday — he had three days and he needed more than three days. The Friday after.
He also needed to know what was above the surface building. The geography texts had not covered this region specifically. He had a rough topographic sense from regional maps he had studied at age ten. He needed more than rough.
He thought about Orra, who had watched and held information for years and given it to him when the time was right.
He thought: eleven days.
He began planning in earnest.