Having finished out one ending of the game already, I was curious to find out where you can obtain the key to the escape elevator in the back of Benny's Room. I didn't find it anywhere in his room and it wasn't on his corpse at any point that I've killed him.

Normally I'd say this just isn't an accessible area, but unlocking the elevator via the console leads to an underground area where he apparently dynamited his way into a Vault (poss. 21) This leads to a series of rooms full of supply lockers and finally to another key locked door but this opens to nothing when unlocked via console. So I'm not sure if it's an unfinished/unused area or it has to be activated some other way.

Thanks for any help.

Good question. I suppose someone checking out the door in GECK is the only way to be sure.

Could find the door reference but not the key; it leads into the Vault. Anyone know if it's open able from the other side?

Looks and sounds like this was a planned addition that never got off the ground. Perhaps the idea was to chase Benny or something, as it does in fact lead to Vault 21's interior map. There's also a small cut-off section of Vault 21 unrelated to the area in question but still looks like it might've been part of something that got scrapped.

Thanks for GECK suggestion.