Vatican Cameos is a phrase used in BBCs Sherlock when Sherlock is about to open Irene Adler's safe [as well as John's wedding]. The phrase first originated in World War 2. It was used when a non - military person, who was armed ( gun or knife ) entered a British military base.
In WW2 "Vatican Cameos" was a code word for when an armed civilian or non forces personnel entered an army base causing everyone to be on high alert or duck and be ready for a fight.
