Police procedurals thrive on formula, but even the most reliable shows need to shake things up once in a while. The Rookie has done exactly that through its documentary-style episodes, a recurring gimmick that began in Season 3 with “True Crime” and has returned almost every season since. These mockumentary-style episodes parody true-crime docuseries, framing Mid-Wilshire officers as talking heads while weaving in body cam footage and 911 calls.