He entered the store brandishing a handgun and threatened the store manager and his employees. The manager ran to a back room despite the orders from Demarcus to stop or be shot. The manager was able to retrieve his firearm and came back to the showroom.
This must have surprised the criminal, singe handguns are difficult to obtain for law-abiding citizens in Chicago. The gunman and the manager exchanged shots and the robber was hit three times. He managed to stagger from the cell phone store where he collapsed and dies on the sidewalk.
The criminal’s two shots missed and no one was hurt. Again, even in Chicago where self-protection is seemingly frowned upon, a good guy with a gun saved lives.