That sudden convulsion and the way Gary's eyes suddenly open startles Nitou, to say the least. He jumps back, then rushes back towards Gary. "Gary? Gary!" He's shaking his friend, trying to shake him out of it, to do something, and then...

...then the siren goes off. Nitou slumps back and away from the body, freezing there in the sudden horrible realization of what he's done. Did he...did he just kill someone? Did he just kill his friend? He scrambles farther and farther away from the corpse--he made Gary into a corpse, why is this happening?--and takes off into a run.