The Perron crosscheck was gutless, brutal, and the kind of clear, intent to injure, play the league should absolutely bring the hammer down on. I can't imagine it happens, but I'd have NO issue with ten games even. It was unambiguous chickenshit and dirty.
I was watching the game and in-game I genuinely wondered whether Larkin just collapsed. It was really scary, there was a scrum in front of the net and all of a sudden he's out cold, and face down. Watching the replay, he gets it a bit up high from Joseph (which people can debate the greasiness of) but he gets knocked out falling into Kelly. No issue with the roughing calls on those, but they're on a completely different planet than what Perron did.