21 feet used to be the rule, as far as I know it's been moved to 25 feet. That's the lethal force rule for an armed individual with a knife. If they're within that footage, you're in immediate mortal danger per the law. A knife isn't something to fuck with, and it's on the armed suspect on how it goes. Especially someone with a violent recent history with use of a knife.

I'm not sure what people expect to happen, the cops shouldn't be getting taking to a trauma hospital because someone is having a mental health crisis, there needs to be another agency involved to ensure everyone's safety. We haven't gotten to that point yet unfortunately. And even then, whatever mental health professional shows up may not be enough and it still just goes this direction. Not all people can be talked to and reasoned with. It's on the person who has the cops called on them to not be in that situation. He escaped once, stabbed people, and then had another mental health crisis. I'm not sure what you think the proper route is to go at that point.