“He must think about what else can he do with his life.” Very true. He is the best ever and he has nothing to prove. Mr. Carlsen, please quit pro chess and open a school with a cool building, good teachers and reasonable tuition.
Magnus suspected that there was a mole - a leaker - in his inner circle, someone very close to him. So he prepped an obscure line he had never played before, and his suspicions were confirmed when Hans fell for the trap - Hans admitted in the post game interview that it was "a miracle" that he prepped for that opening in the morning prior to the game - yeah sure. Magnus did not bolt the tournament because he lost a game - he stormed out due to his feelings of a supreme betrayal.
Another guess is that his computer was hacked and his preparations were stolen or leaked.