The Decompression Windows are a new feature in Dead Space 2. They are large windows that you can shoot in order to cause a vacuum that will suck anything in the area out into space, including Isaac. Shooting one will trigger a sequence where all Necromorphs in the area are sucked out into space, and Isaac slides across the floor, towards the window. The player has to shoot a red switch at the top of the window in order to close it. If Isaac doesn't shoot said switch, it's an instantaneous death.