At the end, the son and the mother...

They could've escaped. If you just witnessed two dead bodies out in the woods and planning to take their car, hurry the f@ck up! Why would you stay in that same place and eat their snacks like nothing happened? - the killer might still be lurking around you idiots

and the son intentionally let his mom get bitten. It didn't look that hard to hold on to the noose stick, he kinda let it go like die b!tch