There's an achievement that asks you to expose Lord Regents crimes. How do you do this?
Expose the Lord Regent's crimes and bring about his arrest
Go into the mission "Return to the Tower" and go to the broadcast tower and talk to the announcer who is there, he will give you the code to access Lord Regent's safe. Go to the safe, located in his room, and then retrieve the recording inside, broadcast this to get the achievement.
This is the non-lethal way to complete the level, as such DO NOT kill Regent.