The Battle of Bunker Hill The Battle of Bunker Hill is an Institute main quest in " Fallout 4 " . Detailed walkthrough . Father orders the Sole Survivor to go to Bunker Hill to reclaim some escaped synths , held there under the protection of the Railroad . The player character will have backup from a courser designated X4 - 18 . Exit the Institute and proceed to Bunker Hill . Optional : If Shadow of Steel has been completed , the player character can warn Elder Maxson about the Institute ' s plans , and he will ask the player character to kill the synths when the opportunity arises . If Tradecraft has been completed , it is also possible to warn Desdemona that the Institute is on its way , which will allow the Railroad to anticipate their arrival and lay an ambush . Both groups can be warned or ignored , however despite Desdemona and Maxson saying they would have had no idea of the Institute ' s intentions if the player character had not informed them , all three factions will be present at the hill battling , regardless of the player character ' s actions . At Bunker Hill , the battle begins only after the player character meets with X4 - 18 . He explains the situation to the player character and calls in backup , at which point the player character can pass a hard persuasion check to get more synth relay grenades . ( Note : If both the Brotherhood and Railroad were informed , this second piece of dialogue will be unavailable and the courser advances towards Bunker Hill after the first dialogue . ) The main doorway into the settlement is locked , requiring the Sole Survivor to walk around to the east ( right ) side of the settlement where an opened door can be found . Alternatively , it is possible to climb the trailers to the right of the locked gate and jump over the fence . The inhabitants of Bunker Hill will cower during this firefight , so it is likely that most if not all of them will remain alive ( due to varying " essential " statuses ) , despite the free - for - all taking place around them . Once inside Bunker Hill , there should be a small doorway into a utility basement behind one of the counters . After following the catwalks to a room far in the back , the player character finds the runaway synths Z3 - 22 , B2 - 57 , Y9 - 15 and F6 - 33 . Here the player character has three options : Regardless of choice , a new objective will be added to report to Father on the roof of the ruins of C . I . T . . The roof is accessible from the easternmost staircase inside the main entrance of the ruins . After a short discussion about how the Commonwealth has declined , Father speaks of Bunker Hill : The quest concludes , and if the player character ' s good standing with the Institute is preserved , Mankind - Redefined begins . Behind the scenes . The title of this quest is a reference to the historical Battle of Bunker Hill , an important conflict of the American Revolutionary War occurring near Bunker Hill in 1775 . Contrary to popular belief , the bulk of the fighting during the Battle of Bunker Hill took place at the site of the American redoubt on Breed ' s Hill , not Bunker Hill . The Bunker Hill Monument was erected at the site of the battle , on the peak of Breed ' s Hill . Thus , both historically and in - game , the Battle of Bunker Hill takes place on Breed ' s Hill , not Bunker Hill .