„Graceful Exit” is a missable achievement in the 5th episode of the Battlefield Hardline campaign. You can’t get spotted during the entire mission. Using taser, takedowns, throwing rocks etc. is fine as long as you don’t get spotted. Follow the route I show in the video below for a fast and easy way to get this achievement done. You will also unlock all other optional achievements from this mission („Their Own Medicine”, „Knock Knock”).