Regulation time in the NHL is followed by 3 v 3 next-goal-wins overtime for 5 mins. If that doesn’t break the tie, then it goes to a shootout. Three shooters per side to start. If it’s still tied after that, then each side picks another shooter, and this continues until one guy scores in that round (as opposed to neither or both).
In this case, the other guy had scored already, so by not scoring, the game ended in a loss for the guy in the clip. By touching the puck, his shot attempt had started, by losing control, his shot attempt ended in a ‘no goal’.
It’s particularly enjoyable for fans of not-the-bruins because the guy is a douche. A good, skilled player, but dirty (fined and suspended for dangerous play many times) and does stupid things, like licking opponents. He’s an easy guy to dislike, so it’s fun to see him screw up.
This kind of screwup is uncommon, but not unheard of, but it’s a particularly egregious example.