Am I the only crazy person who would have tackled the guy, knife or not, after the first thought that he was about to stab my babies? 19 stabs?? I would have locked that man down with pistol to forehead before it got that far. (Not shot him, well...unless he didn't stop...then maybe in the foot...)
Edit: Actually, that's easy to say now, reading the story. But the people were probably in complete shock...who knows how I would have reacted given that moment. Rage definitely comes to mind though.