My belief is that Anderson wanted to win by submission at all costs, even if it meant losing trying to do so.
He came out in his Gi, never before or since has he done that.
At the end of the fight when his hand was raised, he held up his Black Belt, not the UFC belt. Never did that before or since.
Leading up to the fight Chael talked about how Anderson probably got his black belt from a happy meal. Chael made fun of Brazilian children growing up in the mud who have nothing to look forward to. Chael made fun of the Nog Brothers talking to a bus. The Nog brothers of course along with Anderson are the only people in all of MMA who were able to submit the legendary Dan Henderson in combat sports. And Dan Henderson is Chael's teammate.
This is not to say Anderson waited until the last minute to submit Chael. If he could have in the first he would have. But he promised Big Nog that he would submit this loud mouthed american, it's documented in the film Like Water. This is something Anderson promised before the fight took place.
And he did. He almost lost it all because he was willing to go out trying like he told his master he would.
Big Nog gave him his black belt. Big Nog let his arm snap and didn't tap. Those guys take BJJ seriously. It's not "gay" or a "Happy meal" toy like Sonnen would have you believe.