My fellow lifeguard judged that the guy was going to push or hit someone, and made the instant decision to make himself the target instead of any pool patron. In discussion afterward, we all agreed that it was a good decision. You don't try to defuse situations, you enforce safety.
The only call that ever got seriously questioned and led to a hearing was when a college football linebacker type was in trouble, but the lifeguard couldn't get him under control to bring him to safety; the guy kept trying to climb on top of the lifeguard, which just endangered them both. Frustrated, the guard punched the guy, which sent hands to nose instead of grabbing the guard, which allowed the guard to get him under control and bring him to safety. The hearing decided the guard had to make an official, public apology to the guy, and since it was accepted no other action was taken.
Not even two weeks later, another big guy was in trouble, and it gave my fellow guard a chance to show he'd learned his lesson: this time, he swam close but just out of reach, and the guy lunged for him, which got him closer to the side; the guard repeated this about six times until they were close enough he just grabbed one of the lunging hands and set it on the pool lip. It was very creative; usually if someone is too big and too out of control to get into a carry and bring to shore, you wait until they're out of energy and then move in.
