Question: When Ryan is descending back into the atmosphere in the Shenzhou, two pieces pop off the landing module after the big tracking shot. One appears to be part of the heat shield, and the other looks like an O-ring from the window. 1) If it really was a part of the heat shield, wouldn't she along with the Shenzhou have burnt up in the atmosphere and 2) If that was a part of the window, shouldn't it pop out due to the pressure differential? Or, if I'm wrong about those two parts, what are they?
Answer: The heat shield separates before landing. If it didn't the solid fuel engines behind the shield that are designed to give a soft landing wouldn't work. It doesn't separate until the capsule has slowed sufficiently to mean it is no longer needed. I don't know what the other piece that separates is but it is nothing to do with the windows. It comes from under the capsule so was behind the heat shield.
Question: During the scene in which Matt detaches himself from Ryan so that he does not pull her away with him, why didn't he bounce back towards her when the rope snapped taut? Was there something that kept pushing/pulling him away that I missed?
Answer: If they had been tightly tethered to the space station, he would have bounced back toward her. But her foot was only tangled in parachute cords, so that when the tether snapped taught all it did was begin to pull her away from the station as the parachute cords gave more and more slack, slipping more and more loose as they drifted further away.