Buena Vista ( mission ) Buena Vista is the seventeenth mission in " " . Walkthrough . The first thing you will notice during this mission , if you normally have your UI set to mini - map , is that it isn ' t working . This is due to strong electro - magnetic interference and high levels of radiation in the area . You will simply have to do without . Another thing to note is that scurry robot s are very frequent during this mission . They will pop up in almost every other area . Outside the factory . You begin the mission in a snowy field . To the right is a small doorway to a closed in area . The only thing here is two humanoid robot s . If you are wanting to complete the optional objective , kill them both . If not , skip past them and head to the left . Soon you will see a small camp , some graves , and an enticing ceramic pot . Inside this pot is only a Cherry Nuka - Cola , and x50 . 50 cal rounds . If that is enough to lure you over there , you will be ambushed by around 5 scurry bots . If it isn ' t worth it to you , simply skip past it and continue until you see a dried up river bed . Next to it , at the corner of a map , is a small bricked off area , which will have a humanoid robot waiting . Again , if you are doing the optional objective , pop in and kill him , if not , follow the river bed south . Soon you will be fired upon from a bunker by four more humanoid robots , armed with two sniper rifles and two P94 plasma rifle s . You can use nearby rocks to use for prone cover in order to advance closer to them if needed . After this head through a door in the fence at the south . Here will be more Scurry robots and more humanoid robots in trenches , two of which are using plasma grenade s . Continue through this area until you get to a trench with a control panel ( and two humanoid robots ) . This control panel deactivates the force - field doorways you ' ve been passing by . Now you can get to the main door to the factory ' s entrance ramp . You can get to this from either the doorway right next to you , or through the doorway further to the north that you passed earlier . It is suggested that you take the northern gate , as the gate next to you leads to a Behemoth . This is best avoided unless you are doing the optional objective ( if the case , see more on the Behemoth in the Optional Objective section ) . Once at the main gate there will be another console . This one will require you to use your science skill , which will then open the gate . As soon as it opens you will see the remains of Paladin Lancelot and most of his squad . Take care of the auto - cannon in the doorway and head down the ramp to enter the factory . Inside the Factory . When you approach the bottom of the ramp , move the one of the corners of the doorway . If you enter immediately , you will be ambushed by 6 + security robot s , which when all firing in unison , add up to quite a bit of damage . Standing in the corners lets you fight them in pairs of two . After that is taken care of , you can now destroy the first power node . Unlike the previous mission , they do not auto - repair . They also have quite a bit more health ( around 15 times as much ) , so it may seem like shooting it doesn ' t do anything , but it just takes a while . Once it is destroyed , head through a doorway on the south side where you will find another console . This will play a message from the Vault 0 logs and mention the Hellion project , which will be found in a later room . The door behind this console leads to a room where you can find Initiate Percy , who is near death . After a few last words , he succumbs to his wounds and expires . Now head into the hallway , where you will meet a few more robots , including a loadlifter robot . Across the hall is a room with another console . This console will open the door at the end of the hallway , allowing you to progress . Go up the staircase and you will now be on a walkway with a view over the next few rooms . Here you can snipe the robots from a distance , including three Loadlifter robots . When finished with that , be cautious as you continue down the walkway as there will be 6 Security robots and a humanoid robot with a Vindicator minigun waiting for you near an alarm console . They are fairly grouped up , so burst fire or grenades will take care of them quickly . Continue up the stairs and wait a moment . At the end of this walkway is a laser turret that has been modified to fire rockets . You can either kill it or wait for it to go below ground and dash for the ladders to the ground floor . Cross the room and you can either proceed through the doorways or you can climb a ladder up onto another walkway . Climbing onto the walkway gives you the tactical advantage over the Robots in the next areas , as lying prone on the high ground will make it much harder for them to hit you . If you climbed up the ladder to fire from above , climb back down and head through the doorways . Now you will be in the room with the Hellion . It isn ' t actually related to any objective so you can ignore it . There are three paths to take from this room . A door at the left , an opening at the top , and a door at the right . Since you have to go through all three , it doesn ' t really matter which order you choose . To the left will be a room with more laser - turrets , except these will be more true to their name and actually fire lasers . There is another door at the top of this room , which leads to another power node . When it is finished off , return to the Hellion . Now for the door on the opposite side of the room . If you climbed onto the walkway earlier , this room will be empty , but if not , it will contain several humanoid robots . At the end of the room is a door to the last reactor . Destroy it and again return to the Hellion . Now for the opening at the top of the room . This will be to a catwalk that leads to the reactor . It is guarded by a variety of robots , but isn ' t too heavily guarded . The reactor consists of two turbines and a single piece in the middle . Destroy all of it and head out to extraction . Though it is a nuclear reactor you just destroyed , it doesn ' t have any catastrophic consequences to the structure . So don ' t worry about having to race against the clock to get out of the factory . Optional Objective . The secondary objective , to destroy all the robots in the area , is fairly straightforward . Just kill any robots you see and make sure you check every room . This will mean that you will have to face the Behemoth avoided earlier in the walkthrough . If you want to face it , head to the entrance ramp of the factory and enter its yard area . As soon as somebody of your soldiers walks in , the doorway will throw up a force - field to prevent you from moving back through . The sudden force - field kills any member of your squad , who was unlucky to stroll through the doorway at the appropriate time . However , it doesn ' t force - field the entrance to the south , so you can still retreat . Along with the Behemoth , there will also be several Scurry robots in the area making things more difficult . The Behemoth has quite a bit of health , more than any other opponent you ' ve faced so far , and will be a challenge . It is best to fight him in turn - based mode as it will be easier to manage your group and use stimpaks efficiently and quickly . If you are willing to use an exploit to fight him , you can simply move through the small doorway previously mentioned . You can easily out - range the Behemoth , so if you move far enough away you can simply snipe it while it stands stupidly in place , or runs away . If it moves away , just shoot at it some more until it charges again and repeat the process . Level design notes . It seems , that an optional entry point was planned through the roof of the factory . The idea was canceled , but some of the level structure remained . When passing through the middle of the factory , a sliding door may be heard opening and closing at certain intervals . The door is located between 2 of series of chambers on the roof . The opening in the floor on the roof , where ladder presumably was located , is in the area above the rocket - loaded laser turret . When looking from outside of the factory , many catwalks , barriers , windows and vantage points can be seen , but the area remains inaccessible .