Just then you hear a noise could be heard from outside the walls. You start screaming in a futile attempt, but it does not work at all. You pound relentlessly on the walls and do anything to get the attention of someone, anyone, that can hear you trying to get out. At the moment you think that you have made headway, a gas starts to enter the room. It starts out slowly, but then it shoots out faster. What is this stuff, you think to yourself?