The Walden Pond quest doesn't complete. It's marked as cleared. I killed everyone in the shop basements. When i'm inside the basement, the quest marker is located at the exits (usually the sewers exit, unless i'm close to the shop door). When i'm outside, the quest marker is located at the sewers entrance. Talking to the Raider in Concorde doesn't give me an option to say "yes, it's cleared".