Here we see Luna and Jones running through some type of Imperial facility. (A garrison of stormtroopers is running the other direction on the opposite side of what appears to be some kind of rail station.) Note the tall, bony droid running behind them. We glimpse this character in the background of another scene, when Jyn ends up cornered in an alley by stormtroopers, and we know Alan Tudyk (Firefly) plays a motion-capture character in the film. It's a good bet he's going to be this metallic sidekick.
