The whole point of BCS was the transformation of Jimmy McGill to Saul goodman. Jimmy was a morally flexible guy with a crooked sense of justice but was always somewhat good at heart. He put brakes and stopped midway during his elaborate plans multiple times because of his goodness of heart. It was always the question of what event will finally lead him to cut the brake wires forever. As we always knew his brakes were a person. And now it's gone. Transformation is complete. This was one of the most melancholic episodes of BCS and it was very well done!