The first question about this video is, did a police officer use unnecessary and excessive force to take this woman down? But what else he could do? She was an obvious threat to him in this situation?
After the double leg takedown he went for kimura hold probably to bring her arm behind her back to keep control, detain and handcuff her. We were able to see a lot of videos where cops are having huge problems to detain people on the streets and this could be a good way to do it.
In the background of the main video scene you can see a woman using self defense groin kick on a cop. It doesn’t end very well for her.