Lack Of Oxgyen?

In the case of lack, oxygen has some proven statements. The pervious case that I have to consider this was on flight{Name}where the plane has gone down dues to fault in the pressure in the cabin/cockpit where both pilots had no idea what has to happen to cause the plane to drift. Was this the same case with MH370? What I consider is pilots, turns, and drift of the plane of the consider flight path.
      
In the pilots, the captain was very highly trained and even posted videos of "How to fly a jet plane."
So how can this pilot not notice the fault in unpressured plane? This raise consider about pilot suicide did he decompressed on purpose but made it has realistic as possible? We will never know until the black boxes are found.

The next was the turns that were made on the flight of MH370. These turns were very high probably of a deliberate change in the flight path. But with the turn they consider the pilots were trying to head back to the airport, could it have been possible that the pilots were lacked of oxygen and had no ability to fly the plane. Because the lack of oxygen does indeed limit your ability to fly the plane has been proven when a testes area was decompressed  and the guy job was to solve a simple puzzle and he had to fail to solve the simple puzzle. Then the consider question why was there no communications the ground and why would the transponder turn off we will never know.

Shows the struggle of having the lack of oxygen can do it to you with writing a simple sentence.

Resource
Topham, Gwyn, and Bridie Jabour. "Flight MH370 Investigators Consider Oxygen Starvation as Cause of Disappearance." The Guardian. Guardian News and Media, 26 June 2014. Web. 09 May 2016.
This evidence shows the high likely possible of the oxygen starvation. This also connects to the flight path how after three turns the plans then goes in a straight line. Also explains the effects of lack of oxygen and how it could affect the brain.