In Massachusetts we have a, "Duty to retreat," for self-defense. If I am attacked I have to call 911 and have them on the phone, tell them I am trying to avoid someone who is trying to kill me before I can act in self defense. Even then, the burden of evidence will be on me to prove I did everything I could to de-escalate with video, etc.

Uber drivers here have cars wired for video and don't talk to the passengers if they can avoid it.