Any comparison to the speed of light immediately invokes other concepts that wouldn't apply to panning, so it's probably a bad idea.
There might be situations where it makes sense to map an angular speed to some sort of absolute speed, but it just doesn't work in this particular example.
The specific situation where it makes sense to map an angular speed to some sort of absolute speed is if you're told - or have some way of figuring out or knowing - the distance of the camera to the two objects (including if it is very highly zoomed, which it obviously is, from the perspective we are shown).
in this sense - if there is an intuitive sense of the distance of the camera and the high level of zoom - it makes sense to speak of an object leaving earth at the velocity that lets it stay in the center of the frame as we pan.
There might be situations where it makes sense to map an angular speed to some sort of absolute speed, but it just doesn't work in this particular example.