As I understand it, while he's being processed, a prisoner is supposed to always be under enough physical restraint (handcuffs, shackles, or both) that a Taser, Mace, or a baton will be sufficient to control them no matter what they attempt to do.
The rules have changed dramatically over the past fifteen years thanks to the ACLU lawyers.Now you can't put your hands on an inmate until he gives you a reason to.Then after he punches you in the face you have to be sure that you're not too rough when you restrain him or else he will file a lawsuit against you.So after the assault if you don't get fired over your take down technique you can go to court and watch them ignore the part of the film where you were assaulted while they zoom in on your actions.Hopefully you didn't lose your head and you get to keep your house and job.