This takes place during the scene when Ray and his kids just left their mother's house. They are driving and Rachel says she needs to use the bathroom. Ray pulls over and she gets out and runs towards a river where she wants to pee. All of a sudden she sees lots of dead people floating down the river.

I was just wondering why that was. I don't think it's a slip-up per se, but if the aliens killed them they would have either been harvested and pureed, or shot with the ray guns that wold have disintegrated them.

How are they in the river?