Beginning with the Doom II engine, moving walls and ceilings (e.g. doors, lifts, rising stairs, crushers) may be either normal or "blazing": blazing sectors rise or fall much more rapidly than normal sectors. A blazing door, like a normal door, cannot close if a player or monster is directly beneath it, but instead bounces off the object and reopens. One would then expect to hear the noise associated with a blazing door opening (DSBDOPN); instead, however, the normal door-opening sound (DSDOROPN) is played.