<We're all as good as dead. There is no hope.

Just goes to show you, it's always something.

If we can escape the light-speed gamma blast--and those on the far side of the planet might--we'll at least have some warning on the cosmic rays. "Almost" the speed of light might still be quite a delay when measured across a travel distance of light years. The side of the Moon away from the blast would be a good place to be. It would be many days before the Moon would rotate you into view of the blast, and it might be over by then.

Of course, when you eventually go back to Earth, things are really going to suck.

Besides, I'm going to be deader than a doorknob in a lot less than a million years anyway.