Hi there. When I say "shot in the back," I unsurprisingly mean that one has been shot in the back. At any rate, this Code of the West that you describe is very much a topic of debate in this movie. The Coens, in this chapter, walk the viewer through the experience of encountering Scruggs, hearing his own explanation and justification for the way he leads his life, then illustrating how he could also be viewed as a remorseless killer and psychopath. It's all in fun, of course, but this chapter and the movie as a whole are a debate over Western virtue - what does it mean to be a good person in this world?