Now that they've broken through the wall, they can run through the lower life form and get to the top of the wall. But the water flea smells like sewer water, and they can't get above the ground. They stomp on it, but it's too heavy and they're too scared to do anything about it. Finally, they make it above ground, and Mr. Asimov tells them that the radiation levels are going up. They hide in the stairs, and then they see that the woman is back at the ticket counter. They jump up and hide behind the counter.