Scene Context: While working near Sector 4-B, a slack loop forms in Sarah's safety tether behind her back, which gets snagged by the ejected cover.
Essence of the Phenomenon: In microgravity, a tether does not hang down as it does on Earth. If there is excess length in the system, it can drift freely in space, forming loops. Upon a sudden jerk, such a tether stops behaving like a soft line and begins transmitting momentum like a rigid structural element.
Scientific Basis: Safety tethers during EVAs are necessary not only to keep the astronaut near the hull but also to control their kinematics. A sudden tensioning of the tether means transferring momentum from one body to another. If the inertial reel lock engages during this, the system stops paying out slack, and the jolt becomes rigid.
Current Limitations: Microgravity is unforgiving of even a small amount of tether slack. In space, it does not look dangerous until the very second it turns into a snare or a momentum transfer channel. That is why tether management during an EVA is regulated as strictly as tool handling.