I would imagine something like this could set quite uneasy, as if I were single and by myself as a host on AirBNB, would definitely have the same concerns! My first thought is that he more than likely was possibly intoxicated after going out to a bar or something and having a few drinks? If coming back that late at night, I would imagine that's what he was out doing, and would explain the strange mishap. However, there's really know way of knowing 100% for sure what the "motives" or reason behind this incident was, so taking precautionary actions moving forward to avoid situations like this and any uncomfortable circumstances would definitely be the smart route to take.
Is there a restroom connected to the room you're renting out to guests?
I would honestly suggest a good smart lock for guest rooms to help differentiate doors and areas of the house other than common spaces of course, easily for guests to identify and access, and maybe even considering a lock of any kind for your room and areas you would rather not be accessed by guests to avoid this as well.
We just got this new lock a couple months back and absolutely love it! It syncs directly to my AirBNB calendar, sends guests emails with key code and instructions as soon as they book a stay, disables codes at time of check out (and accurately lol), and auto updates itself for me. I don't have to do a thing or have to worry about keys or anything myself, it's awesome. We've gotten tremendous feedback from guests about it as well, as it just makes the whole booking and checking in and out process so much simpler and easy to go about, and actually based off what guests of ours have said as well, actually makes them feel a bit more secure or "at home" I guess you could say.
Here's a link to check it out, I highly recommend it!
https://www.amazon.com/AirLocking-Smart-Lock-for-AirBNB/dp/B0759NPC5Y/ref=as_sl_pc_tf_til?tag=airloc...
