A visual parallel I have noticed throughout SW is the image of a Palpatine goading his new apprentice to kill a defenseless person. He does it with Dooku and Yaddle, Anakin and Dooku, and finally Luke and Darth Vader (Anakin). Each time he encourages them to do something that goes against their morals (killing a friend, a defenseless person, or their father) and the choice they make is telling to who they will become in the future. Luke is the person to break this cycle when he refuses to kill his father after seeing Vader’s mechanical hand. He looks to his own hand and realizes that to destroy his father is to become him. He holds fast to his ideals in the face of Palpatines attempts to change them. It’s a nice way to keep consistency with Palpatine’s character and form of manipulation.