How is this scary? How does it make sense? (SPOILERS)

I guess for people who are really afraid of being buried alive, the ending might be scary. Not for me.

Ditto for people who have never contemplated death before.

But it did nothing for me.

The only thing that is mildly disturbing is the thought of becoming so obsessed with something it leads to to making such a dumb choice.

But the truth is, he could simply have tortured the killer until he told him what had happened to his girlfriend. That way, he would've found out the truth, and not been buried alive.

So not plausible, and therefore not scary.