A man stands there, naked, covered in blood, and holding a toothpick. He looks down at the mangled corpse of his victim, and smiles. Then, he looks around at the room...there are no doors or windows. The only openings are two square holes in the ten foot high ceiling.
Fortunatley, a rope is dropped down from one of the holes. The man walks over to it and grabs on. After being lifted up and out of the room, he shouts "next item: a screwdriver." And then he is escourted away.
After a time, a naked, unarmed man is thrown into the room through one of the holes. Another naked man is thrown through the other hole, armed with a screwdriver. The two men look around. The room is spotless, with no dead body and no trace of what had gone on before. The two men turn to look at each other. And then...