Scene Context: Les sees an isolated white dot in the viewport and states that Sarah has become a satellite of Mars.
Essence of the Phenomenon: A body that separates from a spacecraft near a planet does not "hover" in place. It continues moving via inertia within the same gravitational field and transitions into its own trajectory.
Scientific Basis: Orbital motion is a form of continuous freefall. If two objects in orbit are separated, they begin moving independently, though under the influence of the same gravity. Even a slight difference in velocity or heading gradually diverts them onto different trajectories. That is why an astronaut torn from the ship does not "stand in space" but continues flying as a separate body on their own orbital path.