Lucas didn't expect Preston to hold Karen hostage and even say so much just to get him to kill Frederick.
Although he had just been watching everything from the perspective of an outsider, he couldn't help feeling some sympathy for Preston, who had been educated and raised in such a monstrous way, especially after hearing that Preston's mother had been killed by Frederick. But he was still surprised that Preston asked him to help him kill his father.
If Preston really hated his father so much, he could have done it himself since he had countless opportunities to do so. Why would he need an outsider to help him?
"Why do you want me to help you?" Lucas asked indifferently with his arms crossed.
After hearing what Scott said, Frederick immediately flew into a rage. "You unfilial thing! I am your biological father, but you want to kill me! Aren't you afraid of being struck by lightning?!"