It's like the relaxation of a muscle that's been tense all your life, and you didn't even know it was there.
I think that link got spam filtered. It has no activity.
I think that the reason that time seems to go slowly at those times is the adrenaline. With it pumping through your brain, you think, and act faster. Survival instinct, I guess. Wouldn't be a nice way to live though. There's times when you want time to go fast.
You have no idea how on the point you are. Especially for major accidents. Looking back it feels like it took hours because there are so many tiny details that stick out. Important stuff, unimportant stuff. Smells. Sounds. Voices. But all in all, it takes a few seconds at most to go from just another day to a really bad situation. Happened to me in 2004. Hit another vehicle that wasn't paying attention at an ungoverned merge. Still disturbs me to this day. It took perhaps a second from my reaisation that something was going to happen to it actually happening. A distance of maybe 10 meters.In a moments notice, everything can change.