Robert Comsol wrote:
It could be anything. I took it as a corridor because Kirk,Spock, and McCoy enter through the A frame as if they were coming from the port side. (The camera was in the way.)
What I can see in the screencaps
and in the video suggests they were heavily leaning on the port side of the central corridor (okay, no seating banks but probably just wall-mounted folding seats), but they obviously didn't walk in from
the port side to perform an L- or 90° turn.
I don't think it is obvious either way. The camera was in their path if they walked straight to the A frame so they walked in from the right of the camera (or port side) and thus had to make some kind of turn, even if it is subtle, to get around the camera. If you want to think of it as a bank of seats to make your plan symmetrical that's fine as it is your plan.