The instructors did not wait for the students to organize themselves.
The moment Lorna gave the signal, three of them reached out and caught the floating balls nearest to them, and in the same smooth motion, they hurled them across the chamber toward the scattered group of cadets.
The balls flew straight and fast through the zero-gravity space, with nothing to pull them downward and nothing to slow them except the faint resistance of the air, and the students who had been watching them approach scattered in every direction at once.
Most of them managed to get out of the way. Some kicked off the nearest wall panel and drifted aside, others twisted their bodies awkwardly in the air until the ball passed through the space they had just occupied, and one cadet simply curled into a ball and let a throw sail harmlessly over his back.
