Star Wars: Rogue One - 13 Things You Missed In The Teaser Trailer
4. Imperial Sounds
Man, that alarm. It goes off halfway through the trailer, and it manages to throw me off every time. Aside from being distracting, though, it's also a familiar sound in the Star Wars universe. It's the Imperial alarm, which we've heard in the saga before when the Death Star was under attack, so it's an indicator of the Rebels attack on either the Death Star itself or, more likely, the Imperial base holding the plans.
The other familiar sound linked to the Empire is the iconic Imperial March, aka Darth Vader's theme. This plays under the main theme at the end of the trailer, giving it a very ominous tone to finish on and hinting at the Dark Side and Vader himself.