she should have paid attention instead to where she was going because just then she came to a t-junction and the argocat mounted the sidewalk and shot through the open door of a supermarket and straight down the aisle and through a plate glass window at the back almost before most of the customers had time to let their mouths drop open and before any of them had time to jump clear , including those who landed under piles of cans tipped by the argocat .