Rhem 3

Just out of curiosity, since I've already solved my problem by replaying from a previous save....

In Rhem 3 there's a corridor that sequentially lights up when you enter it and has an elevator at the end. I went down the ladder that's concealed by the elevator and did quite a bit of exploring in this area of the game. Later, I returned to the bottom of the concealed ladder and lowered the elevator. I then disabled the "open" code on the door, for some strange reason, went through this door and explored some more. When I got back I realized that I had made it impossible to get back through the door with the "open" code because the button to open it is hidden by the elevator shroud. Is there another way, besides this doorway, to get back up to the surface where the tram is?

If I am correct on where you are right now, Yes - there is no dead end that I have encountered in any Rhem game.
In this case of the big door - I believe if my memory serves me right that you can backtrack all your actions to get back up.
I believe this is the code behind the door you are talking about?

Yes, that's the door. My problem is that I'm on the other side of it with no way to open it since the button that opens this door from the room that I'm in is covered behind the shroud of the big elevator which is now in the down position.

I know that I wouldn't have encountered a dead end if I hadn't undone the code for the door. After I did, I went through the door and it closed behind me. I just thought it would be odd to be stuck in a game with no way out so I figured that there must be some puzzle that I hadn't done yet that would be an alternate way around.

What a great game! Thanks, MaG!

My memory is vague on this but I think there is a lever on the hallway that opens this door if it is closed without doing the "leave it open" puzzle.