A shinobi must not value himself but rather adhere to his village's ideals. A shinobi must always put the mission first. A shinobi must never show any weakness. Jinchuuriki are tied down by a long list of both written and unwritten rules of things that they aren't supposed to do. Playing Peek-a-Boo with the vessel of the Kyuubi is probably at the top of that list. [X-posted on Ao3]