I hope he knew the guy somehow. Maybe they fought at the fair or something. I read that the victim worked at a fair or something. That would be a better ending then he just started killing someone he never even knew. Not that any of it is "better". But you know what I mean.
I dunno ... I read a couple of accounts ... one said that the two had been talking when the bus stopped and they were smoking cigarettes. The guy wasn't upset or anything ... and he hadn't been sitting next to the victim until just before this happened, when he changed seats.
When it comes to backing off someone with a weapon and maybe not going home to MY family, or helping a perfect stranger by pulling an attacker of them and maybe dying, I guess you can say I'm a bad person, because I'm going to choose going home to my family every time. What good am I to the people who matter to me the most if I'm dead because I chose to get involved in a fight that wasn't mine, when I wasn't armed and the other person was?
ETA: And I heard the weapon was the size of a butcher knife, though the account didn't specifically say it was a butcher knife. The whole bus was supposedly bloody though ...
Maybe the victim made a pass at the attacker or something. Remember that happened with those two guests on the Jenny Jones show a few years back.
Pretty extreme response though if that were the case.