Look at the vid, apparently it's justifiable (and even underreacting) to not only arrest someone for jaywalking of all things (lol) but also punch an innocent woman in the face for trying to separate you from accosting the person. I don't get this "holy-unable-to-sin" status that American society gives government workers and it's quite infuriating.
What would you guys do? Resist arrest too? Video tape it if you saw it being done? Try to break up the fray?
As painful as it is to say, in my opinion the best thing to do against an evil government worker is not be violent, so I would have done what the camera person did and get it all on camera (to use as evidence against the person etc.). I've done it before and it looks even worse if the person tries to steal your camera or accost you for it. The woman who got punched by no means deserved it in my opinion, but it's to be expected that she would get punched or worse for trying to defend her friend (which is a horrible truth).