How people handle this level of disaster is always very revealing. In every case I've ever experienced someone kept their head and a solution was found. Usually there was reputational damage but surprisingly most times the actual business bounced back. But it was always the actions of someone in particular in those first hours that made the difference. Thinking you're fucked is unhelpful, because you start talking ab…
While you can and should be the cool head in the room, it's a route to burnout if you end up being the hero who has to keep saving a dysfunctional organization and management from the consequences of its own failures. By all means do your best fix the immediate problem but get the hell out as soon as you can.