hey remember in most places, the landlord has to give you notice before entry unless it's an emergency. Check lease and local laws; in chicago you get 24h. I would just do it and keep bathroom door closed if I were you. It's a super simple install, you put a tee on the flexible line from wall to toilet so that it also sends cold water to the bidet. You can take it off pretty quickly as well, in case landlord needs to repair bathroom stuff and you don't want to get in trouble.

Good luck with your asshole + landlord