Surprised by nakata reaction to johnnie walker [ kafka on the shore ]

I was expecting nakata completely blow out of his minds, shout, or pass out when johnnie walker started killing cats right before him but nakata kept watching him silently until three cats die? its not a small number, and the way he kills them, any person dumb or not, smart or not, would definitely react but nakata kept silent frightened warching him eat cats hearts ? and what, when he finally loses it, he doesn't try to stop him, infact it seems like he obeys johnnies order and kills him for his sake, as if that's the only way to stop him doing what he's doing. I'm not talking about how valueable cat life is but I'm just surprised on his reaction to that, something i didn't expect.