Could you elaborate more, please? I don't understand how uke can't find his body to get up?
This reminded me of being pinned by Ushiro Sensei a few years ago up at Marc Abrams dojo. Even with Ushiro, I could find my body and could figure out how to struggle to get out of the pin in some small way. However, Ushiro made it very clear from his intent that bad things would happen if I did this. He would play "catch and release" a little with me. that is, he'd pin me down, minimal investment and then when I shifted or moved to try and gain back my structure, he'd re-establish it and drop me back down again. So from my experience with him, it was not so much about that I could not find my body, or continuously move, shift, or struggle to find a way...no it was more about the fact that he was one step ahead of me and would constantly adapt and stay ahead....it was not so static as "I am completely imobilized and cannot move or find my body....I could always find it, just couldn't do much with it when I did find it.
A much different game than a completely external or physical immobilization. So, I can see how Mary would describe it as this as you simply cannot orient yourself in a way to re-establish yourself. it requires a different set of skills, and VERY little investment from the guy pinning as he can walk the edge of "investment" which allows for many more opportunities!