Scene Context: Will explains to Les that nothing is "pushing" the lifeboat — it is effectively "sliding down" an inclined geometry created by the stringlet pairs.
Essence of the Phenomenon: In General Relativity, a free body moves not because a "force" pulls it, but because it follows a geodesic — the straightest possible path in curved spacetime. In the novel, this logic is extended: the two stringlet pairs do not merely confine the soliton, but generate a controlled metric gradient inside it — the very "slope" along which the coupled craft slides. This is not established modern engineering, but the underlying idea of motion through local geometric manipulation rather than classical reactive thrust is conceptually grounded in geodesic motion in curved spacetime and in theoretical metrics where the trajectory is determined by spacetime structure.
Theoretical Extrapolation: The scenario assumes that a soliton bubble can sustain a localized metric "slope" for extended periods. If the synchronization of the stringlet pairs degrades, this slope flattens or warps, and the ship no longer follows its intended geodesic.