This room is a tall shaft found on the west side of Ridley's Lair.
In the original game, the shaft's name comes from the fact that if Samus falls down the shaft she cannot re-ascend it. It is constructed from burgundy tiles that appear to be ornate stonework, and may represent Chozo architecture. Visiting this room is not necessary to reach Ridley, and in fact can be a source of frustration. It has three entrances at its apex, center and nadir. If entered from the first two, Samus can make use of multiple midair platforms, sixteen of which are pillars and two are single blocks. Violas are found crawling along most of these.
Should Samus fall or drop to the very bottom of the shaft, it will be impossible for her to climb back up within the room. At the base of the shaft are a pair of Dessgeegas, which hop along the floor, a short bridge and cube suspended over a pool of lava. The lava cannot be reached and is therefore not a hazard to Samus. She can continue into the Zebbo Nest from the base of the shaft.
In Zero Mission, it is now mandatory to explore this room in the normal course of events, unless Super Missiles are acquired early (therefore allowing Samus to skip fighting the Imago). Unlike the original game, there are fewer enemies and more platforms and ledges. These make it much easier to climb up the shaft, no longer necessitating backtracking to previous rooms. The shaft's architecture is much more clearly of Chozo origin and exits into more rooms, including a Save Room, the Ridley Map Room and a new room with two expansions.
The walls and floors are now a dark pink and purple, and the pillars in midair have a fuschia color. Ruins including columns in threes can be seen extending into the background. Halfway along the shaft, the open space turns into a small crevice that the Morph Ball can fit through, leading to an overhang and a pedestal beside it with a Missile Tank on top. From here, there is a short ledge and a somewhat long drop to the bottom of the room. An Air Hole can be found on the bottom left, which spawns Zebbos indefinitely and is a good spot to replenish energy and Missile Ammo. Samus can also lure out a Zebbo and freeze it to use as a platform and re-ascend the shaft. Otherwise, a Red Hatch on the right wall leads into the Map Room.
To get to the new room with expansions, Samus must run into the base of the shaft from the adjacent Zebbo Nest with her Speed Booster activated. This opens up part of the floor, which is made of Boost Blocks, under which is another short shaft leading to the door below. After Samus comes back from this room, she can Shinespark up through the floor to get back into the shaft.
- "Pronged hall" (Metroid/Zero Mission) (via Blue Door)
- Save Room 2 (Zero Mission, via Blue Door)
- "Path over lava" (via Blue Door)
- Zebbo Nest (Metroid, via Blue Door)
- Map Room (Zero Mission instead of the Zebbo Nest, via Red Hatch)
- "Ridley's maze" (Zero Mission, via Blue Door)
- Missile Tank (Zero Mission)
- Halfway down the shaft, on a pillar in plain sight.
- 158 missile tank (pg. 64)
- "Once the Energy Tank [in the Artificial Passage] is yours, record your progress in the save room nearby, then move on to the lair's lower-left region. As you roll, jump and shuffle through the middle of the left shaft, you'll grab a Missile Tank."
- 159 STOCK UP ON PICKUPS (pg. 64)
- "The pipe in the shaft's lower-left corner spits out enemies three at a time. Stand a few blocks away from the creature-hatcher, defeat the enemies that pop out, then collect the energy and missiles that they leave behind. Repeat the process until your tanks are full."
- 160 MAD DASH TO AN UNMAPPED AREA (pg. 64)
- "To the right of the map room, you'll find a long flat walkway near the ceiling [in the Zebbo Nest]. Go to the right end then run left to build up your Speed Booster. Kneel to stop, drop to the ground and jump over the gap to the left while maintaining your charge.
- Open the hatch, tap A to hop up, then hold left to blast off."