I just checked it. The surrounding walls are all at the same height. Behind the door starts a wall with different level, but this shouldn't be influence this room?!
Sure is the issue gone, if I deactivate the ceiling. See also picture #3. Can't find the issue. I edited the walls several times. Could it help to delete the room and create him again?
Cannot tell much from your images, something you could try is to extend the room slightly beyond the walls, to mid wall, in the area giving an issue.
I did notice, in the 2d image, 3 points in the room set up that are not needed, delete them too, 1 on the corners each side of the viewer.
Try to keep images a little smaller, give a better overall picture.
Mike
If that does not help then i would suggest you make all objects except doors hidden, save the file to share here, perhaps Hans or myself could spot something that would help
or... change the room settings so it shows no ceiling... make a copy... modify the copy to show only the ceiling, no walls or floor.....export it...import and position, one drawback is you will probably have to hide it when moving other objects in the hallway