Anyone, after a shooting, will find themselves in a position where they have to articulate what actions they took. Its always best to have an attorney present when that occurs. Before something like that happens, it is best to get familiar with your state/local laws on the use of deadly force.

In terms of "shooting disarm or disable," most people find that when leveling a firearm at a deadly threat, the fight or flight thing kicks in and the gross motor skills take over, and with the tunnel vision and all - people find that center mass of the threat is the best they can reasonably do.