Photo: https://dl.dropboxusercontent.com/u/59263671/Sentry%20button%20doesn%27t%20work.png
I hit this button repeatedly in order to try to make this ship go to sentry mode, to stop bugging me about moving. Even though the button is lit up on the screen, it's didn't work. It's possible the ship was too close to enemy ships, so sentry wasn't working because enemy ships were in range, but I don't think that was the case here. I'll be sure to keep trying out the other screens and commands on future play-throughs.