Destroy the source of the Mutants Destroy the source of the Mutants is a main quest in " Fallout " . Detailed walkthrough . If the Vault Dweller enters Lost Hills and speaks to the Elder of the Brotherhood located on level 4 , or to Head Paladin Rhombus on level 1 , they will both tell the player character that there are rumors of an army massing to the north . The Vault Dweller may also find a file on a military base to the north in the Los Angeles Vault , thus sparing them the trouble of searching . This will , however , require some skill with Science in order to break the files ' encryption . The military base is located a good number of squares to the northwest of the map , far from anywhere else in the wasteland . The desert surrounding it is patrolled by Unity kill - teams , equipped with minigun s , laser rifle s , and rocket launchers . They may also have a few centaur s or floater s with them . Once the Vault Dweller finally finds the massive installation , they need to get inside . There are four mutants outside the base , three with laser rifles , one with a rocket launcher . The Vault Dweller can use a radio to draw the launcher and two of the riflemen away from the base , and earn 1500 XP for tricking them . The mutant who doesn ' t leave holds a tape that contains the door code to the base ' s entrance . Alternatively , Katja can also pick the lock . Proceed to enter the main base . Combat solution . Once inside , the Vault Dweller will most likely trigger the alarm if they are not wearing robes , and mutants will open fire on sight . However , if the alarm is not triggered by chance , one has the option to talk to the first mutant guard , who will bring them to the Lieutenant . There are four which will come running : two with miniguns , two with rocket launchers . Defeat them , then check out the forcefields . The yellow ones can be shut down for a minute by using Repair on their emitters ( use repair without tools , see notes below ) , while the red ones can be run through at the cost of health ( they are harmful ) . There are two computer consoles behind a few yellow fields that can be hacked to take control of the base ' s security systems . The Vault Dweller can alter the robots ' programming on the console near the elevator , and set his radio ' s frequency to match the emitters and shut them down remotely on one in the far south - eastern end of the level . Tampering with the robots will make them friendly , and changing the pest control to " large pests " will kill three mutants on the second level . While the second level holds plenty of loot , the third level is where the Vault Dweller needs to go . They ' ll come across a big , suspiciously empty room . If their Traps skill is high enough , they will find all sorts of land mines and tripwires in here . The Dweller needs to get to the yellow field at the end of the hall , and blast the two mutants there : Krupper and Flip . After taking another elevator down to level four , heading to the left will produce an encounter with Vat Team 9 , a crack squad of mutant soldiers . The right leads to the vats , which is also where the Lieutenant and Van Hagan of the Children are located . If the Vault Dweller enters the Lieutenant ' s office on their own , without being transported there by Flip or Harry , the Lieutenant will shoot on sight . He ' s armed with a powerful Gatling laser and has a whopping amount of 310 HP , while Van Hagan will snipe away with his laser pistol . If the Vault Dweller is dragged here by a mutant , the Lieutenant will interrogate and torture them , then lock them up on level 3 . The encounter with the Lieutenant is entirely optional . The vats control room is down the hallway past Vat Team 9 ' s quarters , the room with all the COC techies . Use the terminal in the center of the overlook room to set the base to self - destruct . If the Vault Dweller ' s Science isn ' t high enough to decrypt the gibberish the terminal shows , they should pick the second one from the bottom , which sets the timer to the longest possible duration and removes yellow force fields . Alternatively , a keycard from one of the techies can be used to automatically decrypt the codes . Infiltration solution . If the Vault Dweller is wearing some robes when they walk into the outer military base map , they can trick the mutants and get in without triggering the alarm . That will let them sneak down to the control room and blow it to pieces without wasting a single round of ammunition . Another approach is using a Stealth Boy and sneaking through , but keep in mind a high Sneak skill will be required as one cannot walk too close to the mutants or they will be detected . The Lieutenant , though , can see through the Vault Dweller ' s disguise if talked to . Bugs . For some unknown reason , if one does things in a particular order , when they set the self - destruct , the timer will go from whatever time set to zero , making the quest impossible to complete .