Corson tried to kick Cairns. The video shows it quite clearly. As much as I would like to see Corson in tonights game, you can't go around kicking people or attempting to kick people.
How about the "check" at the end of period 2? That's not supposed to rile anybody up? He kneed him in the clip I saw. It really didn't look that flagrant to me, but I'll admit bias (My Family, The Leafs, Everything else - in that order) :-)