A bomb that did not go off

I read about this article on the first page of "The Straits Time" and it tells me that a would be suicide bomber had confessed that she and afew people had wanted to blow themselves up. Arccording to her, her vest could not detonate, whereas her husband's vest exploded, maybe killing some people( they never say). When the bomb exploded, and she found out that her vest could not work, she ran away, along with the fleeing crowd. She was later caught and arrested. We must ask ourselves why those people want to do this. What is their motive. How long will they take to realise what they are doing is actually wrong. All this can only be answered when they have all been arrested.