The captain intended to fly into the Petronas Towers or Malaysian government buildings as a protest/martyr revenge action, but after offing the passengers and turning toward land, I think he thought better of it, and just navigated the plane to a watery grave.
This reminds me of an A-10 RTU student and his final flight from Tucson to Colorado.
Craig D. Button - Wikipedia, the free encyclopedia
I think Button and the Malaysian captain both intended to do worse, but somewhere after the initial action, even though they knew there was no turning back, they also recovered a small bit of sanity and at least didn't do more harm than they already had.
Interesting that we couldn't locate Button's A-10 for three weeks. Over land. In the U.S.
Makes me think we will possibly never locate this plane.