cheese it-the cops!

A warning that the police were coming. “Cheese” might be a variant of “cease.” It might also come from the cheese course coming at the end of dinner; in the sense that with nothing else ahead, it's time to leave. In either event, “cheese it—the cops!” was a staple of mid-20th-century crime novels and films, as well as such movies as The Dead End Kids and The Bowery Boys.