That is what I am wondering too, why the 8 minute descent? Why not just dive straight into the ground?
I am still leaning toward terrorism but the 8 minute descent does seem very odd if it was.
Maybe he didn't want to freak everyone out and risk a mob breaking into the cockpit somehow and stopping him.
Unsettled science on this one so far. Until we know more almost everything is blind speculation. Tomorrow a few more pieces of the puzzle may emerge.