My first instinct is that I would not have approached the perp immediately after the shooting. I think I would have remained in my vehicle, and backed the vehicle around to our left so I could survey the perp and be ready to drive away. On second thought, this just puts just windshield between my face/upper body and the second perp (or was that just an innocent bystander that happened to show up, and wisely chose not to get involved)?
I think I would have called for an ambulance from the safety of my running vehicle, aimed towards the road. What would have been the proper "next move"?