No - its not just about a grade. Its about 'honor' , 'ego' , 'self-respect'....competition with your friends and rivals. Stuff like that. I have been through that myself. Performace in the exams is an estimation of a guy or gal's self-worth in India (and probably Japan/China).
And all those things are illusions like fame. The person was unbalanced to start with. He was a bomb ready to go off. Maybe it's a good thing he did not get to build big things with critical functions that many people rely on.