Duty or Dishonor

Duty or Dishonor is a side quest in Fallout 4.

Quick walkthrough

 * 1) Speak to Knight Sergeant Gavil (Bring Danse along will provide some unique dialogue)
 * 2) Search for evidence.
 * 3) Read Knight Lucia's log or pass a speech checks with Lucia
 * 4) Talk to Knight Lucia
 * 5) Shadow Initiate Clarke
 * 6) Confront Initiate Clarke
 * 7) (Optional) Exterminate the Ghouls
 * 8) Confront Initiate Clarke
 * 9) Kill Initiate Clarke or convince him to turn himself in or tell him to leave the Brotherhood of Steel (If you choose method 2 or 3, don't kill the locked up Feral Ghouls Below the room.)
 * 10) Report to Lancer Captain Kells

Detailed walkthrough
Shadowing Clarke will lead you to the Boston Airport Ruins. Upon entering the ruins, you are tasked with finding Clarke. Go to the right from the elevators that requires an ID card, open the door and down the stairs and through a tunnel. In a room to the left is the body of Knight Rylan. Further down the tunnel you'll be tasked with the optional quest to exterminate the ghouls. At the end where the tunnel is flooded, go up the ramp and through the stairwell/tunnel until you get to an underground parking garage. Traverse the underground parking garage until you get to a subway tunnel. Take the subway tunnel until you get to the next platform, this will lead you to a luggage terminal.

Upon entering, take the stairs down, follow this tunnel until you get to a room that Clarke is in, that`s above the generator room with a bunch of ghouls. If you open the generator room and kill the ghouls Clarke will automatically become hostile forcing you to kill him. Also, if you go into the next room adjacent to the room Clarke is in without talking to him, Clarke will automatically become hostile.

The ID card is on the desk that has the [expert] terminal. You need this to open the doors and use the elevators. If you did NOT kill the ghouls and have settled on confronting Clarke directly, you now have three options:


 * Convincing Clarke to turn himself in grants a piece of armor upon quest completion (T-60C torso with 10% AP costs in VATS reduced). The optional quest objective of killing the ghouls is also automatically completed.
 * You can convince Clarke to leave the Brotherhood of Steel, after which you can either lie to Kells about the missing food or blame it on Clarke. Kells will be doubtful of your words at first, but he will be convinced after the you continue with the lie. This option grants 50 caps and some experience.
 * You can outright kill Clarke, but this will yield no armor or weapon rewards, just 100 caps.

After the mission is complete, you can speak with Kells. Even though he states that a team was sent in to clear out the ghouls, the room at the bottom of the ruins will still be populated by them. You can enter, kill, and loot to your heart's content (if Clarke turned himself in).

Bugs

 * If Clarke spots you he may get stuck in an infinite loop of going inside and back outside again.
 * If you kill Clarke by placing a live grenade in his inventory after you promise not to turn him in it may cause the game to register that he is not dead forcing you to reload past save date.
 * If you enter the underground Boston Airport Ruins for the first time while wearing power armor equipped with the Targeting HUD mod, the quest will glitch. Clarke will not initiate conversation as he is supposed to and will always be hostile. Reloading to a previous save and entering without power armor solves this issue.