In both games, this room is an alternate corridor that runs between the Artificial Passage and the "shaft of doom". It may not need to be visited, depending on whether Samus can obtain the Energy Tank in the passage without falling through the floor.
In the original game, if Samus falls through the floor in the Artificial Passage, this room is one of two she can exit into, in order to continue through the lair or try to obtain the Energy Tank from the other side. It is a short corridor of green bricks and pipes, with some tiles in the ceiling and below the left door that resemble chains. In the center of the room are a group of five pillars, with two of them conjoined. The presence of multiple bouncing Multiviolas and Dessgeegas can make moving through the room difficult if Samus does not have the Screw Attack. There is a short bridge above a pool of lava, which stops right before the end, therefore leaving a small gap where Samus could fall or be knocked in if she is not careful.
In Zero Mission, the room's appearance has been altered significantly. It is now a straightforward corridor over a larger pool of lava, and is superheated. Therefore, if Samus has skipped obtaining the Varia Suit it will not be safe for her to progress through this room. The Dessgeegas remain, but the Violas have been replaced by a pair of Holtz. Ruins including brick walls and buttresses can be seen in the background, as well as two supports for the bridge-floor within the lava. The entire bridge is made of Fake Blocks, making it unsafe for Samus to use Bombs against the enemies.