tim van beveren, thank you for the insight. tim: you're welcome. sumi: what might have driven this man to put flight 9525 into a deliberate descent? earlier, we asked a psychologist what may have been going through his mind. >> i think there must have been some really disturbing goingon with this person. i think he might have had some narcissistic injury that somebody embarrassed him somebody hurt him emotionally so hard that he actually got into sort of a rage and what he was doing now, he was flying a mock -- flying amok. he was not running amok, he was flying amok. i think this was a prepared and well thought out action. he wanted to take revenge and take these people with him. sarah: do you think there could have been any way to prevent this tragedy? >> i think whatever they are doing to prevent such sort of things from happening, they are doing. i mean, there is only so much that you can do, and there will always be people who sort of fly under the radar and even escape very thoroughly -- thorough detection of any kind of psychological, emotio