The hospital I work at has a "plan"...sort of...that works on paper. IF everything goes as planned, those not killed/wounded in the initial attack get to clean up. If anything goes wrong, those not killed hide in their units while the others bleed to death.

Sounds cynical, and it is, but I do realize that this sort of situation is a "struck by a lightning bolt while being attacked by a shark" probability event. Just about useless to plan for, save for allowing employees to legally carry the means to defend themselves, which ain't ever going to happen. At least not at my hospital...That would make too much sense.