I believe that all of the military (who made it) are in one location. At the beginning, if Michael, Angel, and Saul's commander would of survived and made it too them, he would of let them know where they should go. (Prob the evac site at the airport.) And that evac site was probaly picking up all the military and civilians that it could until it got overran. And once it got over ran they just gave up that area and took everyone that they could to the main location, whereever that is. It might not be anywhere close to where the party is now.