The logger guy at the end...
Say what you will about Scarlett's character and the alien guy she was working with and how horrible it was for them to lure innocent men into harms way, to be "processed" for her alien cultures food source it seems. I agree it was terrible to see them go through that. However, I was really disturbed by how the logger guy at the end attempted to rape and cut her with his knife. Obviously he didn't know she was an alien, but it seems that he's preyed on women before and he'll do it again. I was disturbed that once he burned her alive he takes off. Out of all of the male characters, he was the only one that deserved to meet that liquid fate.
And honestly, you actually start to feel sorry for her, because you can tell that at the moment she attempted to seduce the disfigured man, she had a complete change of heart. You can see she starts to sympathize with humanity and feels remorse over the things she's done. She even tried to assimilate into human culture, such as trying to eat a piece of cake, but of course since she's not human it doesn't work out.
But anyway, I was just disturbed that the real human monster got away at the end. But, that might have been the point. She gets to experience the beauty and horror of human nature first hand until she dies. Great film by the way, I've been thinking about it for a while now.