if they were in a water practice tank, they wouldn't rise up if they let go because in practice water tanks, their suits are adjusted for buoyancy so if they let go, they would stay where they were, plus, the US had MMU backpacks that alows them to free float, the chinese didn't, hence they held on, IN SPACE
saw that comment on there, how accurate do you guys think it is? China may not be the best but they arent stupid enough to keep a bubble if they faked it. And why would they fake it? they could show how America has lied to the world but using a satellite to find your ice wall :3