It takes a very special kind of person to be a good cop. They need to have a lot of maturity and be able to handle high stress situations very well, making good decisions in seconds. Yes, this cop made a very STUPID mistake that could have cost an innocent human being her life, much less an innocent dog.
This individual cop has made it painfully obvious he is not suited to the job. You don't even use a gun to stop a dogfight between dogs, it's happening too fast and there is too high of a risk of injuring the defending dog. I can NOT imagine how anybody would think it's a good idea to shoot in the direction of a person, even if it had been a real attack. The headline easily could have been "Woman shot and killed by cop during dog attack".
Just as you wouldn't want someone who vomits at the sight of blood to be an EMT, I wouldn't want someone with such poor judgment to be a cop. I hope his butt gets kicked to the curb.