A fortified bank(s)

This building is one of the few that remain open in this besieged city. From the layout, you can tell that it is the bank for the citizens who have chosen to entrust their valuables to the King's guard. The man sitting behind the highly fortified counter is the only one brave enough to work here. A large brass sign is mounted on the wall to the right of the man.
The only obvious exit is south.
A bank teller stands behind a fortified counter
A strong guard watches the transactions