The official story is that Bush did not want to scare the kiddies. So, he could have looked presidential and said, "I have important business to attend to, I must run along..." and show the kiddies how big a deal it is to be president. It's not like he was going to say, "We're all going to die! We're all going to die!" and holler like a lunatic and pace furiously... just because there's important business to attend to, this shouldn't scare the kids. And besides, why keep a poker face for the kids. Is there an Al-Qa'eda agent among them - who would tip off Bin Laden or whoever that Bush knows...