Oh god. This is stupid. Where the hell is Tsukihiko Amo and Kei Tachikawa? Author just want to have a thrilling plot so he neglected some or A LOT of characters. Lol. What a crap. Too many plot holes, 5/10.
@Harjeli Presumably they've been handling other fronts of the invasion, Amo in particular was handling two directions, his and Jin's, on his own. As far as Border are concerned, this wasn't all about protecting one C-class girl, but taking care that all civilians in the area aren't abducted or killed.