If they tried to shoot the knives out of her hands, the bullets may have ricochet’d and hit the photographer in the background. But there was no guarantee that that would happen so they went for the sure thing. A bird in the hand as the saying goes.
I know cameras are expensive, but I wonder if the photographer threw his camera and hit her in the back or head, that might have caused her to drop a knife or some kind of different outcome. One thing for sure,,I appreciate law enforcement going out every day all over this country, trying to protect the communities and facing dangerous situations!