I would say that when Terry talks to his brother about what could have been the result of his life, it is a moment where one sees the tension between loyalty and disloyalty. It is one of the most famous scenes in the film because it is so emotionally uncomfortable to see the pangs of loyalty hit against the dissonant chords of disloyalty. When both brothers are talking, Charley trying to get his brother to take the bribe in order to be silent, and Terry speaking about how his brother should have "looked out" for him, it is a stunning moment about loyalty and disloyalty in a mob controlled world. Terry reminds the viewer about what loyalty should be and how it stands in stark opposition to what the world of disloyalty looks like. It is a scene where the collision between both realities is present, as Charley embodies disloyalty in how he manipulated his brother, and Terry is tortured in trying to represent loyalty in a world that does not validate it. I think that it is here where we see the greatest symbolic representation of loyalty and disloyalty, simultaneously, in the film.