What happened was Calgary started the game with their 4th line. Generally, the 4th line is your energy/checking line filled with a bunch of tough guys. An unwritten rule in hockey, or a code, is that you never start the game with your 4th line because you're basically suggesting you want to fight. Instead of sending out their more talented players to defuse the situation, as a precaution for their star players Vancouver sent out their 4th line in response and BOOM goes the dynamite.