The gun was drawn when she started turning the wheel to drive around the officer stood in front. You can hear it coming out of its holster, and you don’t see it before then.
However, I’m not condoning the officer’s behaviour here. They created the situation, they should have known better, both reasonably and from their training. What they did was essentially a form of entrapment.
All I’m saying is that she made a mistake herself also by driving the car towards him, and, regardless of whether it’s a police officer or a regular human being, responding with a gun is most likely going to be justified.