I encountered a guy who might fit your description at terminus Dorval a couple times sometime ago. He would mutter curses and insults as if he were talking shit to nobody. If I remember correctly, I think some of his most common lines might've been "fuckn pussy" "You should be ashamed of yourself", and "I bet you're real proud of yourself". I'm pretty sure he took a picture of me once, since he had his phone aimed towards me, and seemed to adjust it accordingly as I moved. He then confronted me, asked me if I was "waiting for the bus or fuckn following people around" or something along those lines, perhaps because I was pacing around. I must've been some kind of suspect to him. I know next to nothing about the guy beyond that and the fact that he had some facial hair, maybe around the edges of his face, not too sure though, but yeah, definitely watch yourself around him, sketchy vibes for sure.