I actually liked the explanation for "let's split up". Yes, it totally makes no sense, but it was made by someone who pretty much wants summer dead, so it never meant to make sense specifically for her.
But, it is a bit baffling that the MC didn't bring up the point: "What are we going to do by looking for the killer? What are we going to achieve by doing ANY of that? Face him off 1vs1? Are you daffy?"
Anyway, indeed. Funny parody. Good shit, lel.