Can I borrow the toilet?

However, the verb “borrow” implies physically borrowing something from someone and that you must give back to it later, so it sounds strange.

I learned that we should to say something like the followings.

・Can I use the bathroom?
・May I use the restroom/washroom?
・I have to go the toilet.
・I’d like to wash my hands.
・I’m just going to use the loo.
・May I inspect the geography of the building?

By the way, most restaurants and shops in Japan have a bathroom, and we can go there without asking.