They used to stick a variety of things in that cavity at the end of the (double wide) corridor when it wasn't being Engineering - usually a sofa and potted plants, but I think the holodeck doors still made and appearance now and then.
Ha, makes sense!One side of the set was left open for ease of access, especially for bringing in shuttles and cargo containers. To create the illusion of a full set, some scenes were filmed with the floor text mirrored when painted and then the image was flipped.
I think adding the booth and second door to the open end would be a great way to close off the set for your 3D game.
I'm actually now looking for corridor refs for the 'holodeck set' entrance, they used a funny corridor config at that turn. There's a half decent one on the drexfiles but haven't really had time to research that.