This is a good argument for shot placement. While the victim choose good locations and was effective at disabling the criminal, the shots were not immediately fatal.
Because the criminal was shot again once he was already disabled, it was murder.
In the Infantry, we can move in on an enemy stronghold, bound forward and through their position while a flanking fire team is laying down suppressive fire. The flanking team can then move through eliminating any remaining threats. At this point, the enemy would positively definitely be disabled. We then check the enemy casualties and secure the site. If we find one alive and on his last breaths, we must provide medical treatment and call for a medevac. If we just let him die, we end up in Leavenworth.
What would I have done at the pharmacy. I would have rolled him over and secured his hands and then rolled him back onto his back. I would then have found something to put under his head to provide aid and comfort. Then I would call 911 to report a robbery in progress and provided descriptions of the one that got away and was armed. I would then describe of the one that has been detained. If the operator asked if an ambulance was needed, I would have said certainly.