Not only that, ongoing video analysis shows that the officer drew his weapon before the car started moving forward. This happens after he shifts his camera to his left hand. Preparing to use deadly force before the threat appears is a hard sell for the claim of self-defense.
Further, as more video examination has occurred, it is clear she was only in that part of the road for a short time, after parking to film and observe ICE from a safe distance outside the traffic flow. She later stopped "in the middle of the road" not to impede anyone, but to yield to oncoming traffic in the lane she was trying to enter as she was ostensibly preparing to leave the area. That oncoming traffic was the truck carrying ICE officers, which she waved through. Instead of continuing through, they stopped and attempted to forcibly detain her.