The Mayasians did not want to admit that internal politics caused one of their own to snap. I think that hard turn to the left is indicative of them calling the pilot's bluff. My opinion is that's when he said "I'll show them. I'll just head south east until they call back." "Hello?" "I'm waiting" "Fuel is running low." "Hello?" "Oh well, F it. This is for Malay democracy! This is for Anwar Ibrahim! Allah ahkbar!"
U-turn as Malaysian opposition leader Anwar Ibrahim admits MH370 pilot is in-law's relative | South China Morning Post
Of course, almost all of that is speculation, but informed speculation nonetheless. Especially if you believe, and I am unaware that this fact has been refuted, that everything was turned off in order - except that which he did not know about. And that directly before boarding he was in the courtroom where his hero was sentenced for being gay.