I want to write a comment that mentions what happens but I also don't want to spoil too much for others reading!
That ending is great, though. It was originally going to be different, too! I wish there were more like it, really. Other disaster films just aren't the same.
I was even reading earlier that this was going to be a Twilight Zone episode, imagine that! The general concept is so great and simple.
RE: 'Miracle Mile' by Steve De Jarnatt Review: The reality of nuclear warfare