Thrawn utters the override code 'Rukh' to stop his Imperial sentry droids. Rukh was the name of his personal Noghri bodyguard in the Thrawn Trilogy of books ('Heir to the Empire', 'Dark Force Rising' and 'The Last Command') which are no longer canon. See more
Look! I'm not happy about it either. For all I know, you're playing a long game to set us up!
I could say the same to *you*. I suppose, for now, we'll just have to trust each other.