Judging by the massive look of the beams and the wall angle I'm confident that Matt Jefferies envisioned this set to be mostly located at the outer hull. However, during the series my overall impression is that it is more often adjacent to the inner corridor because of many scenes were the transporter room corridor extends beyond the angled beams and you see personnel passing by behind the angled wall of this set.
And in "The Way to Eden" Adam actually disapeared behind
the beam on the left side of the room, and I'm sure he didn't do a space walk (space song, yes).
I just checked with the 1966 briefing room construction blueprint and a question popped up: Shouldn't all ceiling beams be parallel to the floor of the room?