Head to the Presidium Commons to the flight of stairs leading to the C-Sec Outpost. Speak to the two citizens arguing at a corner halfway down the stairs.
Go into the nearby C-Sec office and speak to Captain Sommers. The Captain concludes that his plot has been exposed and explains that a C-Sec officer is in custody for aiding Cerberus during the coup attempt. The officer is giving intel on Cerberus to C-Sec in exchange for a lighter sentence, but Sommers argues that he deserves to die for having murdered innocent people. Since the officer is an Alliance veteran, like Sommers, and his actions dishonored the uniform, Sommers feels that it's up to him to deliver justice.
You can then choose how to resolve the situation:
- Persuade Sommers to call off the hit (Paragon) - Shepard admonishes Sommers and points out that he would be dishonoring the Alliance uniform as well if he takes matters into his own hands. Sommers apologizes and shuts down the operation.
- Allow Sommers to kill the officer legally (Renegade) - Shepard invokes their Spectre authority and sanctions Sommers's killing of the officer.
- Warn Sommers - Shepard warns Sommers that he will be arrested if he attempts to kill the officer.
- Look the other way - Shepard pretends to be ignorant of Sommers's plot, allowing it to proceed.
You will receive morality points based on the above actions, and 210 experience and 5,000 credits for resolving the mission.
- Sommers sometimes disappears while you're talking to him, making it look like you're speaking to the couch. The cause for this is unknown and it is an unexpected occurrence. Reloading an earlier save may fix the issue.