While I would like to believe this explanation, the more rational explanation (based on limited evidence) is a cockpit fire from the fan (not the first with this model) which caused the pilot to change course but the smoke quickly overwhelmed the pilots, and thus the plane eventually drifted out to seat and crashed when fuel was exhausted.
Then I am left to speculate that the most rational explanation for why the captain took the pains to rehearse his suicide flight route on his home flight simulator (as per the FBI) was because he had a premonition that the fan was going to catch fire. And Boeing must have thought it rational not to issue an airworthiness directive to have the known defective fans repaired or replaced.
And both pilots must have really sucked at their jobs because the first item in the Boeing 777 Quick Reaction Handbook for smoke in the cockpit is to don the oxygen mask (okay, technically it's the second item but the first item is a memory jog to remind the crew to consider diverting to a different destination, which can be done simultaneous to putting on the O2 mask). Since they were above FL250, in the event that one pilot leaves the cockpit, the other is required to don his O2 mask, so the lone pilot at the controls should not have been caught unawares. So they'd have had to screw up in tandem.
MH370 Pilot Flew a Suicide Route on His Home Simulator Closely Matching Final Flight
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