Beginning to think this might be doable. Richard does it by getting some momentum going kind of like I'm doing here but he seems to get a flick in his head that gives him that little extra. Seems to be about coordination. Finding it helps to keep the lotus really tight and moving the knees towards each other.
Which brings me to my lotus or rather trying to jump back from lotus......Are you kidding!!! OK, I guess I can come out of lotus quickly enough from karandavasana, especially when falling, but my lotus there is pretty loose. Here, in Supta V I have my lotus as tight as I can make it. How the heck are you supposed to unravel that in the middle of a jump back. Have tried binding and unbinding while watching TV or reading but it doesn't seem to be helping., can't seem to unbind without using my hands.
This unassisted version seems to be very different from the assisted.
PS I filmed my sad Knackedrasana, just waiting to download the Deliverance soundtrack before I post it.