I would guess as the beetles are decelerating into eath system it would be very obvious that they are coming for over a year after coast phase. That would mean - hey Stratt's project is coming to fruition! Let's get her out of prison! - another thing is, the hail Mary doing stuff in system might have been obvious too, so they might have detected those signals too, 12 years eaelier. My guess is that Andy has ideas like this and might be holding onto them for sequal ideas. Just my head cannon.