If it was terrorism, I’m surprised he didn’t ditch it into a populated area.
Nothing seems to add up.
Controlled descent with one pilot seems to indicate suicide/terrorism. Unlikely the flight deck lost pressure at exact moment a pilot left it.
Damned good point.
The co-pilot needed to lock out the pilot at the first opportunity he was given. When nature's call caused the pilot to leave the cockpit, that was the opportunity the co-pilot needed. Flying the plane over to a populated city for the crash, would have added a layer of complexity. The co-pilot wanted to do it quick and simple.
The idea of a incident happening to incapacitate the co-pilot at just the time the pilot left the cockpit, seems to be a coincidence with high statistical odds. If they recover the body of the co-pilot, I hope they do an autopsy.