Having had an opportunity to review a high-definition video of Marilyn Mitchell slipping backward and breaking her hip as she walked on a just-mopped floor toward the exit of a Steak N’ Shake restaurant, U.S. District Judge J. Phil Gilbert concluded that the company’s first argument for summary judgment — that it owed no duty to Mitchell under Illinois law, because its employee placed yellow caution signs on the wet floor, including one right next to the booth where Mitchell was finishing a meal &mdash …