This is what it means to me:
10/10ths anywhere, but really only safe at the track, means you are pushing to car to the edge of the handling envelope, and staying right on that edge between really fast times and perfect lines around the course and losing control so that you either are slower or you wipe out completely.
I always thought it was funny how my instructors kept referring to "smooth, smooth, smooth" but when I was in their car, it looked like they were sawing wood with the constant back and forth of the steering wheel. Then I heard one instructor discussing this driving technique as always trying to find the edge of adhesion, trying to push the car as hard as possible without losing control. Each movement of the wheel was to see if there was a little more adhesion to be explored, and as soon as that level of adhesion was lost, a corrective steering motion was made to stay on line, and the whole process began again. This is hard to describe without pictures or video, but I think the illustration I have written about here will be understandable.
