Okay, J. For the sake of argument, I will concede that it doesn't need heating, and can be simply tossed into a room chock full of people from ports in the ceiling, and that this will be lethal for its occupants. Okay, what now? You have a room full of dead folks, and piles of Zyklon B pebbles emitting toxic gas (somehow). You need to kill your next batch of Jews. What do you do in order to prepare that room for the next batch?
And keep in mind, we're supposedly talking about the very efficient, and technologically advanced, 1940s Germans.
After about 20 minutes (after the screaming stopped), they would pump the contaminated air out of the room for about 15 minutes. Then they would send in Jewish prisoners (or other camp prisoners) to pull the dead bodies out. After the bodies were removed they would wash down the walls, ceiling and floor of the gas chamber and it would be ready for the next batch to be murdered.
