I have been experimenting with similar ideas in my game Paradox Vector, but this is not my work. I used cleverly placed teleporters to move the character seamlessly between similar looking areas, so the illusion of impossible geometry is perceived.

https://www.youtube.com/watch?v=TdCUr4b6JaA

It looks in this case that they may have used a VIEW portal of some sort, so the hallway is projecting a view of that room on a passable screen. I have not attempted this approach myself, but it seems like a likely way to try something like this.