RCMP Sgt. Sheryl Armstrong says the incident took place at the Stock Exchange in Nanaimo during the early afternoon.
She says the suspects fled the scene with an unknown amount of cash in a turquoise blue Honda Civic hatchback.
Armstrong says as they were driving away, somebody threw a rock at the car, cracking its back window.
The suspects are believed to be in their late teens or early 20s, one was wearing a black Fox hoodie and the other a blue dress shirt.