Unless the leg was the only target available (obviously not, in this case) he should be reminded to shoot for center mass. Shooting people in the leg/arm/shooting the gun out of his hand mostly happens in movies and on TV. Even Modesty Blaise in those terrific thrillers written by Peter O'Donnell usually shot to kill, and she was a fantastic shot.

I know only one man who deliberately shot a foe in the leg, and he did that to get him to drop beneath a big truck trailer, where he'd have a better shot at his torso. Thankfully, that worked, and the good guy is still with us. Has a Purple Heart and two Oak Leaves, but basically intact. He used a 9mm. The insurgent evidently hadn't read that 9mm ball was ineffective, and died promptly, having sustained a couple of hits in the chest.