I stumbled on something I think you meant to disable before uploading the latest build. I'm going to be vague, since I don't want to help other people seek it out, but I think this picture should make it pretty clear what I'm talking about.
By the way, I have confirmed it's accessible on all floors, not just the 5th.
Also, "bug" report: The Balrog gives 0xp after being killed xP