leaving the mansion via the back entrance was the only way that broke the minotaur earlier, they should normally re-appear after a few rooms
Viewing post in Maid Mansion Nightmare (Lewd 18+) comments
maybe you could hide the back door key to the cellar so you could still keep the minotaur section.
if you're going with that then a note somewhere about the trap door be easier to access, (like in place of the back door key maybe?) since as far as i can remember the only note talking about the trap door was in the attic. altho i could be dumb and forgetting if somewhere else had one lol.