There's an assumption that the brain knows that its support structure, aka the body, has stopped functioning in a permanent sense. I can see how brains could e

There's an assumption that the brain knows that its support structure, aka the body, has stopped functioning in a permanent sense. I can see how brains could evolve to do status checks and respond to survivable events. But, I don't see how it could evolve to have a different response to non-survivable events. What I'm getting at is, do folks who survive report that they had a nice experience? If not, how did brains get a different mechanism for/response to not-survivable experiences?