It's funny, when the cops shoot criminals in a decisive fashion, people criticize the cops for being "trigger happy".
When cops hold off on shooting criminals to avoid bloodshed, even at the risk of danger to the cops, people still criticize the cops.
The cops just can't win.
BTW, in a stress situation, especially with the perp moving around, it's not always possible to shoot him in the knee cap, or arm or leg, etc.
If it comes down to gunplay, it's best to aim for body center mass and keep pulling the trigger until the perp hits the ground. After the perp hits the ground, a couple of "security rounds" in his head are a good idea. Just to make sure.
In the cowboy movies, the 'good guy' can shoot the gun out of the 'bad guy's' hand. That doesn't happen in real life.
It's all about "probability of hit". You do what you can to maximize the "probability of hit" which is why you aim for body center mass.
The larger the target (Body center mass is the largest target on a human.) and the more rounds fired, the greater the "probability of hit" in a disabling and/or fatal wound area.
Even then, there will likey be several misses and off target hits by accident. Especially when the perp is running around like an ape.
There is no such thing as a reliable 'shoot to wound' method. If a 'shoot to wound' incident happens, it's more by accident and/or luck than anything else.
Another issue is that they lacked training and ended up with each other standing in the crossfire of their fellow officers. So everyone was hesitating to shoot for fear of wounding a fellow officer.
It looked like a total lack of training.