Run, Everyone!
Now that we’ve reached this point, it’s time to shed some light on the previous events. He’s known to us as Vault Boy, and he’s been giving us the thumbs up the whole time. Why? Check to see if the explosion caused by the atomic bomb is larger than your thumb; if it is, you are within the radiation zone.
As quickly as you can, round up everyone, and get out of here! At this point, our index fingers are pointing toward the screen, and we are approximately one meter away from it. And the destruction is plain to see: the color is washed out, the lines are jagged, and the shape is ill-defined. I guess that means we should leave as well!