She didn't start from the curb. She starts from over by the group of police and is hopping up and down as if agitated. She is saying something to the police the whole time.
The cops don't even pay attention to her until they're hit with the string. If she were agitated and taunting the cops, they would have certainly noticed and reacted.
You have no basis for saying she was taunting the cops.
She said something that got the police angered. The sergeant and the other four officers to turn right around and eyeball her right away and go right after her. They didn’t look around for anybody else. They looked right at her — all of them. Whatever angered them came from her and apparently her mouth.