The "oh shit" adrenaline spike and swallowing of their heart causes their hearing to go completely dead (no longer hear the engine still going wide open) and legs to go numb (no throttle adjustment). Basically the only thing their brain is processing at that moment are their eyes, what the car is about to hit, and their hands on the wheel trying to avoid it. It's this same autopilot phenomenon that causes people to attempt to start the car again and grind the starter because the engine is still running, or don't recall when, where, or how the engine cut off as an accident occurred.
It's people who've never gone crazy with their car in a safe place to know how it reacts. There is no need to go WOT to power slide. Any time I'm playing around like that, it's blip and let off, next thing you know the rear end is sliding out 10 feet and coming to a stop because you're not even in the throttle any more. It doesn't take much. I've naturally developed a reflex of immediately letting off the throttle when I've intentionally forced over steer, without waiting to see where I end up.... by then it's too late. That said, shit can still happen, so I never do stupid shit in places where there are obstacles to avoid 😀
Worst trouble I ever got into was almost clothes-lining a guardrail taking a sweeping 1/4 cloverleaf off ramp at 70. Was high as a kite smooth sailing until about 1/3 of the way through the radius suddenly tightened up sharp with no warning... all 4 tires squealing, took everything I had to trust the car to slow down on it's own and NOT TOUCH THE BRAKE PEDAL... and let me tell you the brake pedal is terrifyingly seductive when you see a guard-rail zooming in for a close up and get an inch away from your passenger side mirror... The first and last time I did anything crazy on an unfamiliar street... I had never taken that off ramp before in my life /face2desk