The Nuclear Option (Brotherhood of Steel)

The Nuclear Option is both a quest and achievement/trophy in Fallout 4.

Synopsis
With Liberty Prime granting access into the Institute, the time to eliminate the organization as threat in the Commonwealth has finally come.

Brotherhood path

 * 1) Upon speaking with Elder Maxson, the Sole Survivor may commence their assault on the Institute and its scientists, in which they will need to eliminate as many scientists and synths as possible, as well as assassinating Father.
 * 2) Entering through the robotics facility, the Sole Survivor will encounter heavy resistance from turrets and the surviving synth army, and must be dealt with in order to proceed further into the Institute.
 * 3) Dropping down through a hatch in the robotics facility, the Sole Survivor will find themselves in the bioscience labs, where they must travel to the reactor entrance, where it is seen that the blast doors have already been activated.
 * 4) Arriving at and taking the elevator to Father's personal quarters, where Father himself will be encountered, and must be convinced, one way or another, to give up his security lockdown override password.
 * 5) The Sole Survivor must then travel to the Institute's advanced systems, where they will need to access the reactor chamber. Depending on whether an evacuation was called or not, a heavy synth presence may be encountered here, and must be dealt with in order to proceed.
 * 6) After activating the reactor housing, the BoS will be shown having acquired the Institute's teleportation technology, with Proctor Ingram teleporting the Sole Survivor to the Institute's relay control room. It is here where the Sole Survivor will need to speak with Elder Maxson, and decide the fate of the synthetic Shaun child.
 * 7) Through the relay control room, the Sole Survivor will teleport to the Mass Fusion rooftop, where Elder Maxson will conclude the quest line while explaining the future of the Commonwealth.