Yeah, but generally falls are when you've been on the move for awhile, possibly pushing your maneuvering abilities to the limits or judging something wrong. When you're through quite a bit of a race and fall, it's natural for your body to completely shake it off and attempt to get back, determined to make something happen still.
In her case, the place of fall was in a moment without any real challenge at the very beginning (catching a bad spot and/or edges digging in wrong can and does happen though), so the body hasn't had time to really get the anxiety out of the way and into positive adrenal actions on the body.
As with everyday behavior, any two people often act differently in the same situation. We all prime and condition our minds differently, though once you increase the sample, similarities in action definitely pop up.
I'd say I'd probably get up right away. But I didn't just experience what would probably be the most embarrassing and ego-crushing event in my life.