After the military, it seems the only requisite was "People who died before the invasion". They even seemed a little surprised by Pratt's military background.Chris Pratt plays an army veteran, who is still in shape. By right, if the world's militaries had used up their most of their active military forces fighting the aliens, the next in line to go, would be the military reservists and veterans. So techinically Chris Pratt's character should have gone in even before the world wide draft started.