On a submarine base, the topside watch would carry a 1911 and a rem 820 shotgun.
On the pier marines would have M16s and 1911s.
But there is no one inside the sub that is armed.
Like the base, it would be considered secured
rem 870
Now the second a gunshot was heard, the master at arms would unlock the Amory and every SOB on the boat would be armed.
This can only be done due to the close proximity of the crew to the armory.
On a base, the size of Ft Hood, I am afraid there was no way to do that.