and ends up in the layer of the evil Cracker46
However, Cracker46's lair was still 1,500 miles below the surface. Above it, the rocks are liquid, thus impossible to dig through.
Meanwhile, up on the surface, zombies have invaded and left only 4 people alive.
However, the zombie apocalypse ends when a 300 mile wide asteroid crashes into the Pacific Ocean. The heat from the impact creates a cloud of rock vapor which engulfs the world, boiling away the oceans and burning or melting most of what's left. The result is Cracker46's base 1,500 miles underground is the only habitable place on Earth. The four zombie apocalypse survivors die in the heat wave from the asteroid impact.
But, where can she drive off to? The surface of the Earth was destroyed. Anyway, Cracker46 manages to get out of the van.
The old gas station happened to be sitting on a nuclear waste dump, and the glow was radioactive, although he didn't know it. He runs inside, but the floor collapses under him, sending him falling into a massive underground lake of nuclear waste.