Fallout 3 (Walkthrough) with DLC's -> Dukov's residence and Seward Square
A Stalinist-style building right behind the entrance to the Warm Collectors . Dukov is a Russian who lives in his estate by the river with two women (Vishenka and Fantasia).
The house is stocked with alcohol and Jet, and Dukov has a special "Dukov's Key," needed to complete the "Finish Him with a Headshot" quest. You can kill Dukov (he's armed with a 10mm submachine gun) or steal the key.
The Preacher in Seward Square
There are several options for completing the quest:
1. Collect the charges. The mines in the alley are not activated and do not detonate when approached. Only the preacher detonates them, and only if he sees the Traveler or a hostage. Therefore, if the protagonist's "Stealth" skill is high enough, it is possible to collect all seven mines and five available nukes (one in front of the barrels by the slide and one behind them, one in the shopping cart, one by the pile of rubble opposite it, and one on the carousel) without being seen by the preacher. The remaining nukes are unavailable.
One solution is to use Dogmeat, to whom the preacher does not react. At the end of the alley, ask Dogmeat seven times to find a weapon, and she will bring anti-personnel mines; five times she can bring nukes (ask her to bring ammo). However, this demining still does not make the alley safe, as the explosions are scripted.
The Traveler can use the Stealth Boy and quietly collect the charges.
2. Prevent the explosion. This can be accomplished in one of three ways: kill the preacher directly, simply leave the scene, or lure any enemies to the northern end of the alley.
The first option is to shoot from a position out of the preacher's line of sight (his Perception skill is 6). However, caution is essential, as if the madman spots the Traveler, he will order them to stay put, and any movement will trigger the explosion.
The second option also allows you to collect all available charges without further interaction with the characters.
The third option involves luring a super mutant or centaur, which the preacher ignores, to the northern entrance of the booby-trapped alley, activating the Stealth Boy, and sneaking through to the opposite end. The enemies will kill the preacher with the first shot or spit.
3. Detonate the charges. If there is no need to collect the planted mines and nukes, you can talk to the hostage and convince him (Charisma 3) to try talking to the preacher so that he will "listen to reason." After this, he will run towards the preaching madman, and then the Traveler should leave the alley.
Reward. The Traveler can only receive dividends in the form of collected mines and nukes. Killing the preacher or the hostage by any means will not affect karma.
Source: ru.fallout.wikia.com
See also:
Fallout 3: L'Enfant Station (South)
Fallout 3: Dickerson's Chapel
Fallout 3: Arlington Library