Thank you for reviewing, I will try to finish my idea.
Yes, you are absolutely right, the dragon is the thing that keeps rooms outside the loop. Balancing room visits with concurrent obstacles is the premise, however teleporters, while offering shortcuts, can distort the overall flow of the queue.
Also, it doesn't help the queue updates only in new grid positions - think of the snake game, but you can walk over yourself, and only the head moves (and maybe let the old head in place, create a new one when you exit the body, maybe one more mechanic... and that's a new snake - Maybe call it hydra or something).
There's a pretty big jump in difficulty from step 1 to step 2 of the puzzle, but I ended up scrapping my idea for a prologue, because of time constraints. Guess I should be better next time!