We've discussed tachypsychia several times, the phenomenon associated with a perceived deadly danger that often includes, among other things, a subjective sense of altered time. Most commonly, the reports indicate that things seem to slow down and sharpen in detail.
Science has looked at this a few times, and a recent article by Burkhard Bilger in The New Yorker, "The Possibilian," on David Eagleman shines another light on it.
(I spoke to this earlier in a post, but it's worth mentioning again. That post was more about the notion of living in the past, and included a short vid to demonstrate an effect.)
Eagleman apparently fell off a roof as a boy, and the feeling he had when he fell stayed with him. As a professor of neuroscience at Baylor, he decided to explore the experience, and had the knowledge and tools to do it.
He and a grad student, Chess Stetson–how's that for a name?–came up with something they called a "perceptual chronometer," a timer strapped to one's wrist that would allow numbers to flash just beyond the threshold of normal perception.
But even the biggest roller coaster wasn't enough to trip the fear needed for most people.
They found an amusement park ride: Zero Gravity. Called "scads," for suspended catch air device—there are apparently only two of 'em in the U.S.–the way it works is this: You get lowered via a rope back toward the ground; when the rope is released, you drop a hundred and ten feet backward onto a net.
Apparently the safety record on these things was perfect until the one in Wisconsin had a problem: The net wasn't fully in place when a twelve-year-old girl hit it, and she fractured her skull, and spine, in ten places. I expect if I knew that going in, that would certainly help trigger my fear of death ...
Anyway, the experiment was to drop people wearing these timers and have them look at the things to see if what a lot of folks felt subjectively translated to reality. Did their brains actually slow down time?
And the short answer is, No.
During tests, run first in 2007, nobody could read the numbers, nor has anybody been able to do it since.
There are all kinds of explanations for why the human mind does this sharpening and slowing business when Death comes to call, and the article, here, is fascinating reading.