Seward Square

Seward Square is the section of Washington, DC where Reilly's Rangers' Compound is located.

Mad Preacher with the nukes
There is a man standing on the second floor of a building in an alleyway near the headquarters entrance. The alley has been rigged with mines and nukes that he detonates if you try to get close to him. There is a hostage on one end of the alley, who you can talk to. If you are looking at the mad preacher when he detonates, he waves at you. He also dies in the blast.

If your stealth is high enough, you can sneak through and pick up the frag mines and multiple mininuke (there are four: behind the barrels by the slide, in the shopping cart, across from the shopping cart, and on the merry-go-round). Even without the Light Step perk, the explosives will not detonate if you step on them, as they are intended to explode only when triggered by the preacher. Alternatively you can use Dogmeat to find ammo, to pick up the mininukes, or to find weapons, to pick up the Frag Mines. If you remove all the nukes and mines off the ground, the Preacher can still cause detonation if he sees you in the alley. You can talk the hostage into confronting the man using charisma, but he gets blown up in the mine field. Only other solution appears to be sniping the loudspeaker guy from a distance.

Note

 * When the Mad Preacher yells "Trees! trees! to the north! But they're deadly, and they will be consumed by the GREAT FAT WORM!!!", he is referring to Oasis. He also appears to be in great pain yelling "The sun why does it burn? MAKE IT STOP!!".