Re: 490 Predictions/Spoilers
Think of the fox's chakra as being like a glass of fresh squeezed lemon juice. In its current state, naruto is using a watered down version of the fox's chakra that is only half as potent as that which the fox truly possesses. If naruto wants the full power of the fox's chakra he must get the full potency of the kyubi which is only accessible by having the other half of the fox's chakra. The down side to this though is that the fox's chakra as it is right now is rather dangerous to naruto's health. At 4 tails, naruto already gets severe damage so if the kyubi achieves full power than the damage to naruto will be likely lethal even at lower levels. As for the fox wanting out, its more along the lines of the fox wanting to be back to its full power but it can only do that with naruto's help but if naruto does do that it will cost him his life which the fox knows but does not care about. As for the key allowing the fox out, I think that is meant to refer to the method of transfering the fox to something or someone else since right now the seal blocks such methods but with the key this is now made possible to safely without risk to the jinchuriki. This is of course partly theory on my part but if the kyubi seal is anything like any of the others than its obviously possible to transfer the bijuu from host to another without costing the host its life if a proper key is had unlike gedo maza which rips the bijuu out costing the jinchuriki his or her life.