Sounds like the officers got lucky. Plain clothes, not identifying themselves, onlookers thinking it's attempted murder... in some parts of the country that will get you shot.
If an officer refuses to identify themselves, it's not a lawful arrest, it's a kidnapping. I argued at the time that someone would be entirely within their rights to defend themselves in this circumstance. No doubt the DA would press charges but do you really think a jury would convict?
I have no doubt they would (assuming survival).
Would you bet your life on it? Or on the officers in question not gunning you down for your troubles?
They have no problem with turning you into a corpse on the street, but, unlike your run-of-the-mill serial killer are probably not kidnapping you so they can turn you into one in their murder basement.