1) Take smartphone from pocket.
2) Open audio recorder, press record.
3) Put phone back in pocket.
4) Meet with openly creepy guy.
5) Turn recording of this idiot talking about being to another world in to your Vatican supervisors.
6) Have a drink with your friends as Vatican officials take creepy guy away to the insane asylum.
Problem solved.
If he fights it, that's your opportunity to take him out before he gets to full power, and you won't be found at fault for it.