Does anybody know how to access it? I know it involves using the 'beam here' cheat to warp to the glass roof, and then I forget what to do after that. The room is below the chapel – it's a small part of the map that was never used, but it hints that IO were going in a whole different direction with the mission. I saw it on YouTube ages ago, but I can't find anything about it now; Google also turns up nothing.

I never heard of it.