Someone tapped the PA system twice before speaking.
“May I have your attention ZMart shoppers. May I have your attention please. For the next fifteen to thirty minutes, please secure your wallet, purse, and other valuables as it has come to our attention that a Member of Congress has entered the building. Repeat. Please secure your wallet, purse, and other valuables. An all-clear announcement will be made after the Congressman has left the building. Thank you for your attention and caution in this matter.”
With appropriate re-wording, such an announcement should be publicized during the weeks leading up to an election–local, state, or federal.