Well, it's not overseas... you are right.
But, AQ/friends MO says they would detonate one bomb, then detonate more as people are moving to the exits. Look at Madrid. I'm pretty sure those people panicked. I think it's pretty hard to assume that everyone will remain calm in a situation such as that.
Some will panic, a handful here and there. But, most won't and some will go into combat mode even if they have never been in a combat situation before. Some are born with the talent and don't know it, there are some in every crowd. Most will be a little confused and hit the ground until they can figure out something better to do.