Lucivar had given Callista a chance to resolve this peacefully.
He asked to talk privately but was refused and continued being underestimated.
If anything, giving her a chance was Lucivar being understanding for the sake of Thalia.
But if he continued being pressed then he wouldn't endure it and smile like a good little dog.
From his past of doing nothing but good things—he learned that if he only takes it and smile, people would take him for granted. Never again will Lucivar let people do that to him, if other people wanted him to be good then they would need to earn it.
"I thought you were a good person..." Maura whispered from behind.
Upon hearing this, Lucivar cackled lightly, "What makes you think that about me?"
"Earlier, you saved the boy... you endangered your life for that boy. If you're this bad, why did you help that boy? One wrong move and you'd be dead, you know that, but you still chose to do it. Why...?"