I’ve experienced this. Someone pulled a gun on me with the intent of killing me. Past memories flashed by incredibly fast in a slideshow sort of format, all in a second or so. I don’t know why it happened, but I figured my mind was trying to find a way out of the situation.
The time I was mugged at gunpoint by two guys was a surreal experience. It was such a calm experience in the sense that neither of the two muggers were aggitated or excited. There was only one gun. During the entire interaction, there were many thoughts of movie like scenes on how to disarm the gun and extricate myself from the situation like a scene from a movie. Having absolutely 0 training in any kind of self defense, I chose to not do anything and walked away unharmed and just lighter in cash. The only thing that changed from that is it was the absolute last time I've carried cash.