I think the way Dex got rid of the "Problem" that was Paul, was excellent!! I did think he was going to kill him, but to set him up that way, so he'd end up inside for good was classic, and very calculating. He probably knew that he would get killed in prison too, because of his attitude and temper.
I think Harry's code may have also played a part in the way he got rid of Paul, because, even though Paul was a bad man, he had served his time, and was loyal to his kids, so I think that's why Dex didn't go all out and play hide the limb with him!!...
I won't kill my sister...I won't kill my sister...I won't kill my sister...