Indeed. Moreover, regardless how depressive the pilot is in the cockpit, he will be way less tempted to perform such a silly suicide action with someone just close to him. We're not talking about a jack-bauer style terrorist here. Quite the opposite actually.
I wouldn't jump to any conclusion quite yet. I've know people who were depressed, even known ones who were suicidal, and none of them would ever want to take 150 other people, mostly strangers, with them. OTOH, I've seen a pretty outwardly-normal-seeming person have a psychotic break, and I can tell you, in that state, all bets based on prior behavior are off... (In fact, changing the subject, I've wondered if Darren Wilson's hard-to-believe description of his encounter with Michael Brown indicates that Brown had a psychotic break. Rare in the real world, but also somewhat concentrated in males his age, and consistent with the very very strange behavior claimed...)