After all that, he tried to kill himself and shot himself in the arm??
Looks like he shot himself right after the flash bang, and just prior to the dog attacking.
Well, with everything that he had going on, I'm sure he was a little distracted and that threw his aim off...I mean - if you have a flashbang going off in one ear, tear gas going off behind you, a dog that's seriously wanting to see what you had for breakfast, and a taser causing you to do the chicken dance, just how straight do you think you could shoot??
We are hearing the round entered his arm, exited, and entered his chest. Makes sense, he was probably disoriented by the flash bang when he shot himself, or the dog was pulling on him when he shot himself. Seems he was determined to take himself out.