@Jack - loved your post. Dying to see what happens with all that toilet paper!
Just want to make sure we're on the same page with the layout (and sorry I'm too computer illiterate to do up any sort of graphic).
So assume you enter the office suite facing north.
So in the foyer you've got the reception desk on the north wall, and the bathroom you just used would have a discreet door on the east wall of the foyer.
The only other two doors out of the foyer are on the north wall, to either side of the reception desk. You are in the eastward room that is to the north of the reception desk.
It follows that there is another room to your west accessed by the other door from the foyer.
There is also a door on the west wall of the office you are in, which also most likely connects to the 'northwest' room. That is the door that had the loud pop music coming through, which music stopped a couple of minutes after you spoke to the receptionist about seeing Cheryl.
Will put a post up soon.