I play sports reguarly, and have been KO'd twice while playing football. I recieved a shot to my temple at near point blank range at both occasions. I wasn't out for long, the first time I literally hit the ground, and woke up within a second of hitting it. I got up immediately, remembering chasing after the ball and walked off of the pitch to get checked over.
Not every KO leaves people behaving irrationally, or temporarily weakened. On both occasions I was slow to carry out alot of things immediately after I went, which is similar to Lewis, not getting out of the car. Although it is also standard procedure to remove the hands from the wheel, it is rather odd he didn't slow the car down at least.
Like others has mentioned too, he was confused and had to use a replay to find out who he crashed into, and what actually happened.
http://news.bbc.co.uk/sport1/hi/formula ... 701124.stm - theres an onboard of Lewis' crash too there.
I think it was a brief KO.