I didn't like the ending, either. What really ruined it, imo, wasn't so much the 'not finding fuel thing' - although that did bother me as well. Rather, it was the fact that the army arrives
just after he does the deed. Yes, it's only a movie. Yes, there are coincidences in movies. But this one just felt too damn contrived.
And I also hated how the woman who wanted to go back to her children survived at the end, as if to say 'See? You should have helped her' or something. Any
reasonable person would not have helped her.