Todd is suddenly pinned to a tree by a horribly maimed Aaron, who has somehow escaped from the crocodiles. This guy just doesn't quit, now does he?
Todd is being held so tightly that he feels like he's dying, until Manchee cuts in just in time, sinking his teeth into Aaron's leg.
Once they've broken apart, Aaron panics and asks about the "sign," which is another thing that Todd doesn't understand. And then they both realize that the girl is gone.
The girl must be the sign, then, and she also must be the real reason that the town is freaking out—not just from the hold in the Noise.
Todd does some quick thinking: Maybe the town can get ahold of the girl and leave him and his family alone. Yeah, it's not exactly a heroic thought process.
Fortunately, though, Todd changes his mind quickly when he hears a piercing scream and realizes that Aaron has caught the girl. He hears Aaron's noise in snippets about a "holy saint" and "sacrifice" and realizes dude's going to kill her.
Todd gets his knife to kill Aaron, though he really doesn't want to have to do so. He starts bracing himself, but Aaron gets to him first, pushing him underwater.
Todd breaks free, and after bashing Aaron's head with a rock, the girl hands him the knife.
Todd tries to work up the courage to use the knife and kill Aaron… but he can't do it. He has a revelation: The knife is a choice. He can decide to kill Aaron with it, but the decision means a lot of responsibility. He knows that Aaron doesn't have long left to live, and he doesn't have to become a killer.
So instead, Todd turns to Manchee and the girl and tells them that they have to move on.