BROTHERHOOD OF STEEL QUEST 07 - Show No Mercy
Triggered by completing Brotherhood of Steel quest 06 - Tour of Duty
Note: You will be facing super mutant enemies exclusively during this mission, so arm yourself accordingly (energy weapons).
Objective: Meet with Elder Maxson
Now that you're acquainted with the main personnel on the Prydwen, return to the Elder and he'll explain to you that he needs nukes. Lots of nukes. And apparently there's a whole bunch in the Fort Strong armoury guarded by super mutants. You can probably connect the dots here to guess what he wants you to do.
Objective: Board the vertibird gunship
Note: There are reported glitches from earlier versions of the game where you can only board the vertibird in power armour, or after traveling to Boston Airport and back. You can also walk to Fort Strong to bypass the gunship issues if you encounter problems.
The marked vertibird on the main deck is your next port of call, so walk over and hop inside to seat yourself behind a mounted machine gun. You'll have a slow and relaxing trip, raining down fire on any random enemies you fly over until you approach your destination. Take that random mirelurk hunter.
Objective: Kill the super mutant behemoth
When you arrive above the area surrounding the armoury, you'll be confronted with several super mutants and a super mutant behemoth. This much larger version of a regular super mutant can be extremely dangerous if you're on the ground (thanks to it's high damage output and ability to throw rocks at you). However in the vertibird it poses little threat as you whittle down it's health. You may want to take the time to kill off a few of the other super mutants running around the area before bringing down the behemoth so there is less opposition when you land. As soon as the behemoth is dead, your vertibird will descend to the ground to let you jump out before it flees back to the Prydwen.
Objective: Secure Fort Strong
Depending on the difficulty level and number of remaining super mutants, you can simply stay on the minigun when the vertibird lands and open fire. The other option is to run for one of the nearby buildings and use it as cover while you take on the remaining mutant forces. There are quite a lot of radioactive barrels in the area (hence the mutant population), so try and avoid soaking up too many rads during the fighting. Enter the Fort on the small hill at the back of the island when the area is free of threats.
Objective: Secure Fort Strong armoury
Upon entry, you'll only have one direction to go. Through a dooor to your left that leads to a group of around three super mutants. Be careful on higher difficulties here as they often like to flank you from different directions. Use an energy weapons to chew through them faster. Another three or so super mutants will be on the other side of this floor for you to bring down as well. Make sure to explore this floor to find General Brock's office in the corner. Grab the Fort Strong key from his desk as it opens the safe in the corner of his office, as well as the locked door back in the entrance room of the fort. A mini-nuke is sitting on a broken cabinet in the corner as well, free for the taking with a green loot box against the wall to empty.
Note: A copy of U.S Covert Operations Manual is sitting on General Brock's desk for you to take.
Now that the looting spree is over, look for an elevator in the middle of this floor (between the two groups of super mutants you just killed) and take it down to the sublevel of the armoury. Exit the elevator when it stops and turn right down the hallway. You may want to enter sneak mode here to get the drop on the supermutants and mutant hounds below. Be extremely careful here as one of the mutants often has a missile launcher which can spell instant death on higher difficulties.
The safest approach is to move down the stairs and quickly into one of the side passages to get into cover, circling through the hallways, taking any enemies in the outlying rooms before engaging the main group in the large central room. When you do attack the main force, make sure it's from a position you can hide from incoming missiles. The mutant hounds will rush you here, so you might want to ready a shotgun for the inevitable close range encounter.
When you manage to bring the two or three mutants and their pair of dogs down, follow the hallway they were guarding to the end to find a security room on your right and a pair of mini-nukes on a table beside some stairs leading down. Empty the security room of it's items before heading back the way you came, leaving the sublevel and returning to the entrance. Just before reaching the elevator you'll run into paladin Danse.
Objective: Speak to paladin Danse
Danse will give you a bit of a lecture with an orange persuasion option thrown in before telling you to report to Elder Maxson.
Objective: Speak to Elder Maxson
Exit the Fort and fast travel back to the Prydwen to report your success. You'll get a handful of vertibird signal grenades as a reward for your troubles.