I just got audibly cropdusted by a stranger.

I'm walking down the stairs to leave my building and I come up behind this middle aged, normal looking guy about floor 7 who is walking slower and doesn't let me pass. So I get stuck walking behind him until we get to the bottom and I KNOW he knows I am behind him. We get out of the stairwell into the lobby and I still don't pass him because the distance from the stairwell to the outside door isn't that far. So we are walking out and he starts looking behind him like he is checking to see if someone is behind him and starts digging in his arse followed by a couple of completely audible stink bombs. Like I said, I'm sure this guy knew I was there.

I have been cropdusted by a-hole friends and I'm sure mystery people throughout life, but never by a stranger in a conspicuous fashion as this. Is this just some dude that DGAF or was he establishing some sort of dominance? I couldn't get a look at his knuckles so I did not engage.