Happens more often than people know.
They usually only find out when they try to pass through the gate.
Missing weapon.
Misplaced cryptographic device or keys.
What they did at Wright Patterson was called our friend and told him to keep us at his house till the all clear was given a couple hours later.
Guess that’s why they made visitors sign in and out back then.
Such things are typically the result of a change-of-command inventory or the cause of one ;-)
A missing bioweapon is extremely serious.