I was working in Ocala, Fl. Our security officer made arrangements with the Sheriff's office for a mock robbery. Staff was told it was going to happen, but not when or how.
About a month later at 4pm, after the bank was closed, a nicely dressed, good looking man in a suit knocked on the glass door. He told the employee he only needed copies for a job interview, he begged her to let him come in and make copies so he could get a job. She unlocked the door and two other men came from around the building and all 3 rushed in. They yelled, used vulgar language,threatened them, and called the staff derogatory names,and waved guns.
The "robbers" made everyone lie flat on the floor and told them do not look up. One girl looked and one of the "robbers" put the barrel of his gun onto the side of her head and said " you do that again and you are a dead xxxx".
Although the bank's security division had good intentions of preparing staff in the event of a robbery, it didn't turn out well. Even though staff knew it was going to happen, at the time it did, we weren't sure if it was mock or real. It got too real. Most were terrified. Within the month 3 people had quit.