Americans hate the word “toilet” and have all sorts of euphemisms to avoid saying it. I don’t know anyone who’d say, “I need to use the toilet.” Instead, people say things such as, “I have to stop at the restroom,” or “May I use the bathroom?,” or “I’d like to wash my hands,” or just plain, “Please excuse me.”
I suppose that any private or public facility is a rest of sorts. The person gets to wash up, comb his/her hair, repair her lipstick, straighten his necktie, etc.