ok, when i read it, i was (initially) very confused.

kabuto placed haku as zabuza's shield from kakashi, but somehow zabuza summoned his free will and stabbed haku in order to help kakashi. he stabbed the only person he cared about to help kakashi!!! i know haku is dead and all, but OH MY GOD!!!

and this is beyond what kakashi can emotionally take, which says a lot, he's pretty much a bad ass. he even tells everyone he's about to go nuts from what he just saw.

i dont even believe that. crazy!