The Star Marine Guards defending the Imperial Embassy
on Arden during the Fifth Frontier War retreated to a Black
Globe Safe Room when locals stormed and burned the compound.
The 100-meter diameter globe neatly sliced through
walls (and a few attackers) to envelope about a quarter of
the installation. Over the course of a month, it resisted fire,
bombs, and other attacks.
When forces from the Imperial Fleet arrived, they used a
coded laser to signal the interior that all was finally safe, but
to confirm the signal, an outside Marine tapped the rhythm
to the Marine song: tap-tap-tap, tap-tap-tap, tap-tap-tap-taptap.
The interior Marines deactivated the barrier, happy at
the prospect of eating something other than stored rations.