Thanks for your reply! That’s actually an interesting idea. Though when you look closely at the first seconds inside the shop (0:24-0:27), you can see a problem with that strategy. Note the hallway to the left of the mirror in the main set. It goes into the depth of the main set, thereby erecting a wall in the theoretical adjacent reverse set. When the camera first enters the shop, its angle shows that the reverse set is much wider than physically possible. I think the possibility of a reverse set becomes viable only around 0:30, when the camera faces the mirror directly and not diagonally.
You can see a clearer illustration of the spatial limitations of a reverse set at timecode 0:57.