Chances are the Officer was carrying a 9mm.And the shot in the cruiser was a gut shot.
Most likely the threat was over at that point.
IIRC there was a bullet hole in the roof of the car
I have to ask another question of the officer:
You just got a 911 emergency dispatch call and are headed to that location with all haste —
Why then are you wasting time stopping 2 kids in the street and having a battle over egos???
As far as he knew they had nothing to do with the emergency dispatch, and if it later turned out that they did, he now knew where they were and where they were headed and could have gone there with backup with an entirely different result.