Also, maybe the tether did move from shape memory, but this doesn't explain Zhai's legs flying up when he is not even moving. A human being's legs don't want to fly up relative to the camera just because. If you don't believe me, watch the bodily control the astronauts doing ISS spacewalks can achieve. Parts of their body don't just float against their will. Zhai, on the other hand, shows us the exact opposite. This kind of "floating leg" visual is often what happens to you underwater. Try it. Don't achieve neutral buyoancy, just go down to the bottom of the pool and hold onto something. Your legs and the back of your body will try to fly up towards the surface. In space, this is not AT ALL the case.