The store has two levels, "G" and "C". You board with your cart at "C" and press "G". Nothing seems to happen. You get it. Then, other shoppers enter too quickly, worrying they aren't controlling their medley of groceries and children. Others are miffed. You, standing next to the buttons press and hold the "door open" button, so that the man using the cart as a walker can board. Then, you press the "door close" button. Their is a pause, during which someone says, "has anyone pressed the "G" button? Then, we rise.