I have to agree. This is the first time Chief has ever disobeyed an order, ever. He did it for the right reason. ...call himself a Captain...DISGRACEFUL, that's what I call him! To leave one of the UNSC's best soldiers (Final Mission), unacceptable. But yes, I think that was a key moment because you see a different side of Chief. A Spartan-II would never do that, but the UNSC has changed now, all those people in the books that Master Chief knew better might not be seen again. One of the only people he know's well on the Infinity is Lasky. Apparently Admiral Hood has been on it to save the Arbiter so that's good that we hear of him.