Something like a "all hands to battle stations", changing all military schedules to constant training or ready/stations, though that would depend on how one manages the military.
Possibly combined with the civilian alert so that civs are also sent back to the safe zone at the same time.
I don't think "training" would be the right thing to do in an emergency. However, it could be nice to add the following:
an interface that allows selecting squads for automatic "mobilization" and/or a burrow for rallying.
when the civilian alert is triggered, set all squads selected for automatic mobilization to "ready" (possibly ignoring those that are already training, not sure about that, in particular as it comes to archers and ammunition management)
assign "defend burrow" orders to squads that have defined rallying points.
Something like a "all hands to battle stations", changing all military schedules to constant training or ready/stations, though that would depend on how one manages the military. Possibly combined with the civilian alert so that civs are also sent back to the safe zone at the same time.