There is a truth to be found in what Jack Baker says about his son: the family are not truly killers, even his boy Lucas.
There’s an interesting type of truth to be found in the statement in regards to Lucas. That he is truly not a killer, at least not at heart. Lucas has murdered, tortured, and has proven not likely to stop such things. Even after his mind has become clear, given an immunity to Eveline’s control from a serum provided by her very creators; he continues his actions with a heightened sense of awareness ( a loose fitting word to how Lucas perceives the world after being pulled from Eveline’s influence). He takes pleasure from his actions, just as he takes disappoint in the failures of the abducted. He’s seeking for something beyond the bettering of his own inventions.
Lucas continued his abductions of individuals, continued acting as if he were under Eveline’s control to make her believe that he was still under her control; Lucas is an exceptionally smart individual, it would not have taken one in order to fool a child, genetically modified or not. Some of his actions are pretending. ( Which brings an interesting point– Lucas had never wanted to kidnap the Baker victims because it was wrong, but rather because he prefers not to physically be harming. The harm that Lucas does is usually through a third party, or object, and even physiological damage but he does not physically assault. Even when faced with potential confrontation of Ethan Winters he runs. He has never murder with his own hands, rather his inventions. It’s an interesting disconnect between the player and the game master.)
While her control over Lucas was short, it did not leave without any lasting effects. Lucas was already mentally ill before the arrival of the tanker. Even before being officially diagnosed he murdered a child by starvation ( once again never really touching, rather a death by neglect ). In some fashion, as a child, Lucas did not understand his actions; while he had understood that he had murdered ( going so far as covering up the murder vis-a-vis the ‘bayou’ in order to remain a guiltless party ), there was the question of why Oliver had died, a very brief question, but still a question. Shortly after diagnosed, he began taking medicine, but Lucas stopped. Factor in the childhood trauma from the physical discipline of his father.
Eveline’s mold touched his mind. It unraveled everything that Lucas had been attempting to keep under lock and key so he could have a 'normal’ life. ( A normal life that he does not base too heavily on his own childhood, although the basics of a father and mother in a nice house stick. He would even argue for getting a job, one that uses his talents to the fullest, although he was never quite successful for varying reasons. He’s an asshole. ) Her 'mold’ was a key to unlocking the pieces of Lucas that were held back; the violent, the erratic, the more meticulous malicious pieces of his mind. ( There is, as well, a heavy sense of PTSD that comes after being freed from Eveline. ) It would be wrong to classify this Lucas as a true Lucas, he is a very complex and confusing person, he does being a 'sociopath inventor’.
He lacks a filter. There isn’t something to keep his invasive thoughts at bay, nothing to guide morality. There are actions, like nail pulling and teeth spitting and subjecting individuals to his ideas; these are things that he most ardently enjoys, things that a little less than kind and more than disturbed. Specifically, there’s a reason to the nail pulling/chewing/ripping, as they grow back quicker and knows that he can not really die, it’s become a way of calming himself.
Yet. Lucas has his moments. The moments where he is helpful, where he isn’t an entire asshole. Purposely leaving video tapes which Ethan ( or truly, any other victim ) can find, leaving the photographs and hidden treasure caches. Lucas Baker is an observer of the Baker family, employed by the same B.O.W manufacturers that had made Eveline; Zoe is helpful, yes, but Lucas is the only one whose not under Eveline’s control. Now, whether Lucas intentionally left the tapes is another question to be asked, another secret that Lucas will not reveal. It is, all of the helpful things he has done, another way at keeping people from assumptions. Keeping people guessing, because Lucas Baker does not like being pegged as one thing. He doesn’t want anyone to have a grasp on who he is, what he wants, and truthfully most aren’t capable of forming a solid conclusion on Lucas beyond asshole.
In a way, Lucas invites sympathy. He has this childlike quality about him, and he can be very charming. At other times ( really, most of the time ) he can be quite repellent, because he can be remorseless and erratic and hes an indirect murderer, and you’re reminded about what he did.