@10 Police use their weapon to end a threat to their lives. As had been pointed out here ad nauseum by 5280 and others, they shoot for center mass. They shoot for center mass, because it is the largest mass of body to hit, especially under life threatening circumstances. I gurantee if you had a gun in your hands, and someone started to pull a gun or knife on you, that due to involuntary muscle reactions, you'd tense up, start to shake, and probably shoot the ground before shooting at and missing the armed threat against you.

Additionally, (and much more importantly), shooting for center mass has a higher likelihood of ending the threat (dropping the motherfucker in his tracks), or at least having the bullet shock his nervous system enough for the officer to gain control of the situation. Center mass has the heart and spine, and you are done if hit in either spot.

Bottom line. If Police shot at your leg and hit you, would you still be able to draw a weapon and possibly return fire? Why should police allow for that possibility? Would that not endanger not only the officer, but also the surrounding general public?