The Nuclear Option ( Minutemen ) The Nuclear Option ( Minutemen ) is the final Minutemen main quest and an achievement / trophy in " Fallout 4 " . Detailed walkthrough . Talking to Preston Garvey after having defended the Castle from the Institute ' s retaliatory attack will initiate this quest , provided the Sole Survivor has a total of at least eight settlements under their control , otherwise the quest Form Ranks will be given instead and must be finished first . Once Garvey considers the Minutemen ready to take on the Institute , he will advise the Survivor to speak to Sturges , who has meanwhile completed his analysis of the Institute data they brought back earlier . Sturges can usually be found in Sanctuary if he wasn ' t sent somewhere else . He notifies the Survivor of a possible backdoor into the Institute : an old cooling water tunnel system . He then gives the player character a holotape with which they can reprogram the Institute Relay in order to teleport in Minutemen reinforcements . He also mentions insistent radiation warnings about the area they need to traverse . Opening the map once Sturges finishes his briefing will lead the Sole Survivor to the C . I . T . ruins . However , the true destination is only shown by the compass and will eventually lead to the flooded entrance to the cooling water tunnels at the river bank directly south of Ticonderoga . From there it is only a short walk until the Sole Survivor reaches dry ground again , so no Aquaboy / Aquagirl perk or mirelurk cake is necessary when opting for power armor . Once underground and out of the water , there is an Advanced - locked terminal to the left that opens a small room with minor loot . To the right one will find a keypad that needs to be interacted with in order to clear the path forward . Proceed through the large , partly flooded pipe that runs below the small room the terminal opened . The path is mostly linear and crawling with ceiling - mounted laser turrets , mole rat s and feral ghoul s . It also involves wading through radioactive water most of the time . Eventually one will reach an elevated walkway with an Expert - locked terminal . From here on the Survivor will encounter hostile synth s , two of which can be ambushed through a hole in the wall right next to the terminal . If one ' s hacking skills are insufficient to open the door , proceed along the tunnel until reaching another door which is locked with an Advanced - locked door . If the Sole Survivor doesn ' t have the Locksmith perk , then another door nearby will take them on a circuitous route that will lead to their destination . Make way through the ruins , picking up a fusion core from a generator , an overdue book from an abandoned classroom and several pieces of combat gear along the way , among them a Stealth Boy . Once arriving at the room where the Sole Survivor saw the first synths through the damaged wall , continue through another large pipe on the lower level into the Institute proper . The pipe exits directly into the Relay control room where one needs to load the Institute relay targeting sequence holotape into the marked console . Doing so will teleport in Garvey , Sturges and several minutemen . Talk to Garvey and accept the Fusion pulse charge before taking charge of the attack on the reactor . Fight through the Institute forces , turrets and a sentry bot , the latter of which can be destroyed before it powers up if one is quick enough ( alternatively , using a nearby terminal will allow it to be powered up before entering its field of view and cause it to become hostile to the synths in the room ) . After reaching an iris - like hatch in the floor and jumping down to the next - lower level , pick up another fusion core from the nearby generator before proceeding to the Bioscience facilities . Dispatch all hostile synths and beware the synth gorillas that get turned loose , should the Sole Survivor venture too close to their habitat . The next area contains a lot of hostile synths including several courser s that usually attack under the cover of their Stealth Boys . The Survivor will also encounter at least one named legendary synth here . Once all enemies have been taken care of , Sturges will direct the Sole Survivor to the Advanced Systems department , only to tell them that it has been locked down and needs to be opened from the director ' s personal terminal . Use the large central elevator to reach Father ' s quarters where he lies dying . The player character may speak with him ; convincing him to help them by passing an easy charisma check will provide the Sole Survivor with the password for his terminal . The terminal ' s password is also available in the desk to the left of the computer . Alternatively , one may simply hack the Novice - locked computer in order to use it to lift the security lock down . One can also make the rest of the mission easier by shutting down some of the synths ( persuade Father for this password ) , as well as opt to fulfill the optional objective by engaging the Evacuation Protocol BD - 2 , which is necessary for continuing one ' s work with the Railroad . If the player character doesn ' t evacuate , the entire Railroad will turn hostile as upon meeting them again . Also , Garvey will hate not giving the evacuation order . Once done , head for the Advanced Systems facilities and the reactor . Securing the reactor involves a fire fight in close quarters . The player character will encounter two named legendary synths Z4K - 97B and A - 2018 , that wield heavy weapons and carry the reactor terminal password . The reactor needs to be shut down and the radiation purge initiated before entering safely to place the fusion pulse charge . Talk to Garvey and let Sturges teleport the Sole Survivor to the relay control room where the Sole Survivor encounters S9 - 23 . After the Sole Survivor decides on how to deal with the synth , they must talk to Sturges . This is the last chance to return to collect whatever the Sole Survivor might have missed in the Institute . Choosing to abandon synth Shaun will prevent the Sole Survivor from receiving Shaun ' s unmarked quests , making the Wazer Wifle unobtainable . Once ready , tell Sturges so and step into the Relay . The Sole Survivor will then be teleported to the roof of the Mass Fusion building . Pressing the detonator in front of them will blow up the Institute ' s reactor and initiate the epilogue cut scene . Talking to Garvey afterwards finishes the mission . Should one have made enemies with the Brotherhood of Steel by this point , the next mission With Our Powers Combined will usually start as soon as one gets in Garvey ' s dialogue range again . Notes . Keeping all three factions alive . The fastest way is to simply become banished from the Institute upon arrival at the Institute , but to get the most out of all main faction questlines while finishing the game for the Minutemen , do the following :