louis was the flight instructor at the neuro academy for carsin's final five years there, it looks like! they'd have left at about the same time. he then went on to fly support missions for the aia and do rescue/extraction for infiltrators, aaaand deserted a year after carsin showed up it looks like. whoops. he's always happy to see former students, but this one could be slightly awkward? (which i would love but it also doesn't have to be)