ID film please

Slasher film, I seem to remember it's Australian, but my memories may be wrong. Probably because of setting. Two young couples head into desert, but their truck breaks down. They meet this stranger. Over the course of the film, this stranger kills three of them, chasing the last girl around a mountain. The girl gets back to the truck, or perhaps the stranger's car, but can't find the key. The psycho catches up with her, knife in hand, but instead of killing her, show her the key, and swallows it, forcing her to disembowel him to get it. The film ends with her finishing telling her story, traumatised.

My first thought was Wolf Creek, but after reading the synopsis (i've not seen the movie) its close, but no cigar.