Robert Comsol wrote:
If you take the original studio set into account, a mirrored transporter room is ruled out, as it would stick out of the wall where the ladder is.
Not only that, but it appears it would also overlap the pocket door just to the right of that ladder alcove (the door that's generally the entrance to the briefing/mess/rec room), and come so close to the corridor wall itself as to be impractical for set construction without some foreshortening.
If, as I suspect, we've probably seen somebody walk past that ladder and pocket door on their way to the transporter room at some point, then the only way to tweak this to work would be to move the position of the entrance to this hypothetical transporter room closer to the A-frame at the end of the short, straight corridor.
Perhaps the best canon argument against two transporter rooms across the hall from each other would be that in "This Side of Paradise" we should have seen two
queues of crewmen in the corridor, right?
Unrelatedly, it would appear that the reason the transport console moved around so much was that it probably needed to be gotten out of the way every time they wanted to shoot a turbolift scene at the lower end of the curved corridor.