Because I'm old...the voting booths are also machines! In the dark days of yore, voting booths were mechanical contraptions. You walked into the booth, and a helpful attendant pulled the lever (the "weapon" in that woman's hand) which set the machine up for voting. You then set various levers next to the candidates of your choice. When you made your selections, you flipped another lever that recorded your votes in some mysterious way, reset all the other levers so no-one could see how you had voted, and opened the curtain so you could exit.