In Philbrick's Freak the Mighty, why does Max go under his bed?

Maxwell Kane lives with his mother's parents. His grandpa made his a bedroom in the basement, which isn't much to look at, but he actually calls it the "down under." When life gets really difficult for Max, though, he hides under his bed. In Chapter Five, he explains that he goes to a special place in his head where his mind drifts like clouds and he forgets everything. Later, Kevin's mom, Gwen, panics when she sees her little boy with a big boy who looks like Killer Kane. Max doesn't know that Gwen panics because he looks like his killer father, so it hurts deeply. Max hides under his bed in his deep, dark basement room. Max explains that it is easier to get to that happy place in his head when he is under his bed. He just stares at the bed springs and the darkness helps to take him away from his problems. Max explains being under his bed as follows:

". . . and before long I'm somewhere else, sort of floating, and it's so cool and empty in there, you don't have to think about anything. You're nothing, you're nobody, nothing matters, you're not even there. Time out" (21).

In conclusion, Max specifically goes under his bed this time because he feels rejected by Kevin's mother. She completely flipped out when she saw Max with her son and it made him feel like trash. She does call to apologize, though, so Max doesn't stay under his bed for long.