This would make the endgame battle much more interesting. Instead of walking with Lyons' Pride while they kill the Enclavers, Autumn calls you to help him defend Project Purity. And then... Liberty Prime and the Lyons' Pride shows up, killing anything that moves. Now THIS would be a real final battle, the kind of final battle that forces you to use EVERYTHING you have at your disposal to fight the giant robot of mass commie destruction and the Elite BOS squad. That would be awesome.