Well, I did some more work, then kept having a leaking issue so I trashed the environment and kept the bunker parts. The outside environment as of right now will not be important, since the first half of the mission involves you retreating into the bunker to escape.
But whatever, here is my latest piece of shit I made in hammer. Don't mind the rest of it, texturing is sure to change as well. I figured this was better than one long stair case, or just a lift.
FRONT
BOTTOM-BEHIND
The first steps. These are also being setup something like a trap, that will prevent NPCs/Players from using it.
I'm going to try and finish the first of it and post a video. You start out kind of helpless and pretty much get to run around till you complete the first objective, which is to retreat into the bunker.