Since he didnt join the scrum per se, I don't think anyone in the NHL will see him as deserving of suspension under this rule.
To wit: the game had ended and it is customary to congregate at the net to grat the goalie and each other. He didnt skate in there guns blazing, he approached his net, where multiple Cats were being idiots, and tapped Barkov on the back of his shoulder and probably said something like "game's over, you're better than this." At any rate his actions made it clear that he was trying to help de-escalate. So class clown grabs him from behind, using his stick as a weapon to hold him in a headlock. I saw nothing indicating he was joining the scrum, he rather got dragged into it by Mr. Good Sport.
Sorry I kneejerked to your original question.