do you think your life flashes before you eyes when your drunk?
I think in this particular case Dunn either
A. had a deathwish
or more likely B. was drunk enough to feel that he was bulletproof.
So I imagine Dunn hits the gas and let's face it, 140 mph in a Porsche is really starting to get it and you don't have much of a chance with that amount of alcohol in your system.
I just see two guys probably laughing it up until they hit the guardrail they never see coming, have an "OH SHIT!! moment" for maybe a second, 2 seconds max and then it's a Tony Soprano "lights out your dead" type ending as soon as they hit the ground at that speed.
Basically one moment your are partying up going 140, the next moment it's over, dead.