Another sound from behind me, back toward the front of the building. Another click, and this one does sound like a weapon being cocked. I look back over my shoulder. Nothing, just blackness—no lights, no target, no options. With my left hand I grab the doorknob, turn it and push. Simultaneously I drop into the lowest crouch—eyes narrowed to slits so I (theoretically) won’t be dazzled if the lights are on through the door.