Moments before this incident happened, a police officer in a cruiser was stuck in the snow nearby, and the crowd stopped the snowball fight and went over and joined together to push him out of the snow and get him going again. Then went back to their snowball fight.
Then this yahoo shows up, gets hit, and comes out with a gun. Everybody calls the cops, and the cops show up looking for a lunatic with a gun. He explains who he is, things calm down.
But he created an incident where other police officers arrived thinking they were about to have a showdown with an unstable man with a gun. Many, many things could have gone wrong and ended up with gunfire all because he couldn't control his temper.