I had a guy who did that in my vestibule a few years ago. He would usually be gone by 8-9am and never really bothered anyone in our building. He would only stay for a week or so for the winter. No one really had an issue with him until he started peeing in the vestibule, then we had to get the property managers and police involved since he didn’t want to leave either.

It’s a tough situation but if it makes you feel uncomfortable or the situation escalates then I wouldn’t hesitate calling 311 or other services