If Lucifer cared, it was really hard to tell. He did let go of Mello's hair. He even seemed to relax for a moment. Lucifer didn't really have a set plan of what he was going to do. He had his goals and he tended to have no problem with 'going with the flow' as the phrase went.
He just took a lot of pleasure in seeing what kind of things would happen as he introduced someone to a world of pain. His leg lifted to plant a sharp boot in Mello's stomach. From there, all Lucifer did was put his weight on it. "How many hours does it take for you to feel pretty?" he mused.