even if it was just the e3 demo from a few months ago that would do nicely for all the fans, they could sent hawks over and send tanks and missiles from the silos. however it is their choice, they said that they were getting most of their feedback from their inside company games so a beta was not needed.
however as the alpha has come out you could follow the pattern of halo 3, so the beta version should come out in a few months and the epsilon build around about october if it follows the previous game
after clearing up the marines in the barracks, master chief turned the gun on himself