The cop was involved with a car, read that weapon, trying to drive away, read that being used as a weapon against him, when he fired his weapon to defend himself from this assault. He had every right to do so and he had the authority of his badge to command them to stop. These ladies, mainly the driver, made a choice not to obey the officer and then to try and run him over with the car. This was not a simple shop lifting situation.
The dopey cop put himself in that danger by trying to enter a moving vehicle. Like the original poster said, he should have taken down the licence plate number, but most cops would rather look for an excuse to shoot someone than do something useful.
ladies thugettes, mainly the driver, made a choice ...