[alnorth]

I dont buy the physics argument, but as jAZ noted, adrenaline can make time seem to slow for you.

Basically, the way it works, is that your brain is normally able to process images from your eyes only X times per second. However, during times of extreme stress when your panic fight or flight reaction kicks in, your brain kicks your perception into high gear. This allows you to process images from your eyes 2 or 3 times faster than normal, so although time moves merrily along as normal, to your panicked perception, it looks like time has slowed down.

This is a survival function to allow you to see, think, and react a lot quicker to possibly save yourself. As a nice added side-bonus, this can kick in even if your life is not in danger, if your in a situation with very high stress.

e.g. idiot driver swerves into your lane head-on, you get the "oh s**t" moment, your brain kicks into survival mode, and you can see the road better, time seems to slow, and you react faster.