No idea. Probably at the discretion of the refs. I'd imagine that if Ott and Miller were tangled up a bit, as they were, and a third guy came in, that an NHL official would have no reason not to give that third player an instigator.
But this is hilarious, really. Calling up Glass has removed all of the narrative that should've been on that game (ie. the Rangers being ****ing terrible and AV getting outcoached, again), and put it all on "team toughness".
This team is straight up broken, and we're calling up Tanner Glass, and playing Kampfer over Clendening.
Is this real life?