Descent into darkness. Literally in this case.
Ever wanted to explore the vast caves beneath the station but found all the minisubs taken? Ever wanted to haul your trench treasures back onto to the station but lost your minisub?
The Sea Elevator is there for you. It's a sparsely-decorated T-shaped room a bit right of the Bar, linked to the rest of the station by a small hallway branching from the maintenance area right of the Arcade and Barbershop. As a corridor between the main station and its outpost in northern parts of the trench caves, it grants crew members of all stations and ranks access to the trench, regardless of minisub availability.
The elevator itself is pretty simple. If you're a regular Biodome raider, you'll find it eerily familiar. If not, don't fret, for you'll find it intuitive enough. If the elevator's on your level, simply stand on the catwalk platform, click on the elevator console, and call the elevator upwards/down. If not, simply stand out of way of the platform first, then access the console. That's all. No arbitrary weight limits, no agonizingly long wait, no pseudo-music to "entertain" you during the ride, just a plain, simple lift.
On the way down, prepare for a descent into darkness. No, really. There's a reason there's huge crate of glowsticks at the bottom. It's pitch black in the waypoint station since there's basically no lighting, and the caves are only slightly brighter. And, for obvious reasons, we hope you've brought your own diving suit and oxygen tank, because there aren't any at the bottom.
It's also a good idea to take that power pick. Though the outpost in the Trench is always there, it's randomly placed in a different spot each round, so you might find yourself staring at an asteroid wall when you walk out the airlock.
There is no vent. Hopefully it should be obvious why.
The APC for the Sea Elevator is in the elevator room, right near the airlocks.
This room gets its power from a reinforced wire line that has an peculiar path. It runs through the maintenance area right of the Arcade and Barbershop, makes a 90 degree turn eastward, does a brief swim outside through the ocean, goes under a wall, and finally ends under the floor of the room with the Sea Elevator APC.