“Only two out of seven went off. We can probably rule out al-Qaeda. They are pros. If they had planted seven, all seven would have gone off.”
Like the shoe bomber?
I am think all of the devices would have worked. However, I think the person who was setting off the bombs made a mistake. That person of interest we hear so much about may have caused the second bomb to go off too quickly and was taken out by his own bomb. He was unable to set off the rest of them.