As funny as it sounds, my understanding is that it's often not immediately obvious in the adrenaline of a life-threatening situation whether or not you got shot. You have to kind of check yourself over and make sure because you literally don't feel pain.
I'm going to be honest, there is a part of me that's hesitant to be so so harsh on the guy, because it's hard to say how you would react in (what you perceive to be) a life-or-death situation. It's not unusual for people not to react well. There was one shooting video like that where the cop did something embarrassing and I had full sympathy and support for him (A woman pulled a gun on him during a traffic stop and shot at him, and he stumbled back and shot her, and he thought for a second that he might also have hit someone in a jeep full of people that was randomly stopped behind her. He was on bodycam just overall losing his shit from having shot her, not even understanding why she tried to shoot him in the first place, and thinking for a second that he might also have also hit someone in the jeep by accident. That I can have a lot of sympathy for honestly.)
That said, you need to not have this kind of reaction if you're a cop. In a personal capacity I have sympathy for him; he learned he doesn't have the right stuff for what he wanted to do; this humiliating display is etched in permanently as his legacy, and he has to find a new job and he's just lucky that no one got killed because of him. In a professional capacity, fuck him and let's all laugh at him rolling around in the road and wailing.
(Edit: Personally, for me the absolute peak of the comedy is when he half-empties his gun, and there's a little beat of stillness, and then out of nowhere he just falls down and wails before starting shooting again. Again I shouldn't laugh because someone could have been killed. But it's fucking hilarious and I can't see it as not so.)