Rydell remembered being taught how you had to use something, anything, if someone was coming after you with a knife, and you were unarmed. If nothing else you were supposed to take off your jacket and roll it around your hands and wrists, to protect them. Now he imagined using the projector, in its bag, as a sort of shield, to ward off the knife he'd just seen, and the hopelessness of the idea actually struck him as funny.