So the easiest way until this gets patched is to obviously run around and get the first 2 objectives, doesn't actually matter if you trigger an alarm... Then once you have the first two you can just be stealthy and get the last one undetected... This will pop the achievementHowever, if you want to do this properly... then follow along with this guide and it will show you the best route to take and still get it done in under 16 minutes for the 3 star ranking: