So there I was, fiddlin' with the remote detonation thingamabobers. I turned them off using a pic of Justin Beiber. Then I promptly left.

I couldn't leave the elevator area on the lower floor. There could have only been...

AN INVISIBLE WALL
This was about as far as I could go. Oddly enough, this didn't happen when I played this game on my Half-Life Resonance Cascade mod, so I think it's room generation's fault

My seed was killjoy

Confirmed.

I had tested this, and it had happened to me. New, Mod-less copy of the game. Though, I can't seem to help you. Try it on a different seed, and test it. It may be seed-exclusive, as some other bugs are.