What was the deal with the tubby fat guy and the bubblegum girl in the bedroom at the gas station? She looks like she's disgusted while she is finishing pulling on her dress, and the fat guy is breathing heavy and sweating. Is she his sex toy or what?
I have a theory on this-since it was obvious the girl was abused, Murphy "saved" her-this would only serve as a purpose to re-enforce the theory he was one of Elvis' illegitimate sons-Elvis had a thing about young women being innocent so maybe it was showing a trait that showed he was related? It was very out of place as Murphy-being a sociopath and all, wouldn't care about her but something about her moved him and he helped her, maybe as a thanks for not freaking out that he killed that nasty father of hers. He knew what he was embarking on wouldn't end well so he made sure she went with the biker gang to keep her out of harms way. It was out of character and I am not sure why they would try and humanize Murphy-however like I said, it was a trait from his alleged father-maybe saving her was the "Elvis" thing to do
The only problem with your theory is that he didn't know about the girl until after he had killed her father. She walked in after he had killed the father and was talking loot.
I'm not sure if handing the girl over to a biker gang is exactly SAVING her! I would think a lot more rape and violence would be heading her way in that scenario. But at least she got out of BFE Nevada.