> If that was actually the case, a lot of heads at FB should roll over this. The logic is simple and obvious, and if the sysadmins and network admins didn't think about this line of thinking then they're overpaid:

You say "if" as if it's a conditional, but surely the fact that it happened proves that no-one considered it (or, I suppose, that whoever did consider it didn't have enough sway to stop it from happening). There are, rightly, so many laws and regulations requiring that safe egress in case of emergency not be prevented, and I can't imagine anyone actually considering and tolerating even the slightest risk of an Internet issue preventing that egress. Well, I guess I can imagine lots of people doing lots of awful and harmful things, but I can't imagine anyone doing it in such a way that it would be this easy to get caught doing something blatantly illegal.

(Or were there safety measures in place that allowed egress, just not entry? I don't know the specifics, since my source is just the news stories that mention that the door locks didn't work and people couldn't get in—but maybe they could still get out?)