As soon as I thought of a nuclear missile heading towards the Pentagon, I immediately thought of the idea that a couple of the Custodians would need to 'ride' on it in order to tinker with its course trajectory. The atomic weapon was drawn by simply creating the outline of a projectile and then 'colouring' it with a photograph of a genuine Perishing missile in order for all its markings to be correct.
With hindsight it is a little hard to see precisely what is going on, especially in the final frame when the missile 'throws' off its occupants. As a result I's probably make the first of the scene's three panels significantly smaller so you can see the entire missile and that the characters are up in the sky. I'd use a similar scale for the final drawing as well, and actually depict Galaxian and Tortoise-Shell Eddie as tiny falling figures.
Air Force One is about to fall to the alien invaders and so is the Pentagon. Mankind's future rests solely upon the flight of a single nuclear missile. But has Galaxian got his co-ordinates right..?