"I like it down under, got the place all to myself and no fear of Gram sticking her head in the door and saying Maxwell dear, what are you doing?"
Max spends his time in the basement because of the solace offers. As a damaged kid, he really values his privacy. He needs to know that he does not have to be paranoid about interruptions or surprises.
"Speak of this to no one, but at some future time as yet undetermined, I will enter that lab and become the first bionically improved human."
Here is Freak's infamous lie. He invents this story about becoming a bionic man because he doesn't want to burden Max with the knowledge of his death. Maybe he's afraid Max will leave him if he finds out he's dying, not wishing to form a bond with someone who will leave him so soon. Whatever the reason, Max decides to believe Freak's lie, despite its obvious questionability.
"But like Freak says later in the book, you can remember anything, whether it happened or not. All I'm really sure of is he never hit me with that crutch."
Max struggles with memory throughout the story. In this excerpt he hints at past abuse which may have compromised his mental faculties. Freak teaches him that memory is completely fabricated anyway. Freak takes this statement as license to invent memories for himself -- a dangerous practice, -- but he does find peace in no longer straining to try and remember events which are lost to him.
"Sure it will hurt. But so what? Pain is just a state of mind. You can think your way out of anything, even pain."
Because of his illness, Freak has learned to master pain. He relies upon mindfulness to accept his suffering. Rather than trying to feel differently than he does, he chooses to think through the complexity and nuance of the experience in order to understand it better.
