Still in the Dark

 is a quest in Fallout: New Vegas.

Quick Walkthrough

 * Locate BoS in Hidden Valley Bunker
 * Speak with Paladin Ramos
 * Make your way to Elder McNamara
 * Deal with the NCR Ranger
 * Speak with Elder McNamara
 * Retrieve 3 Holodisks from fallen Brotherhood Paladins
 * Return to Elder McNamara, and give him the Holodisks
 * Meet with 3 Brotherhood scouts and obtain their reports
 * Give Elder McNamara the 3 scout field reports
 * Retrieve the parts for the air filtration system

Detailed walkthrough
This quest is obtained at the Brotherhood of Steel compound at the western entrance to the Hidden Valley bunker. To gain access to the interior of the bunker, the character needs to either have a Lockpick skill of 100 (Very Hard lock) or perform certain other actions to be able to interact with the intercom, such as:

-> Discovering the bodies of Brotherhood Paladins anywhere (E.g. the REPCONN facility's 3rd floor or near Moe around Black Mountain). The note they have will have a password on it. You can use that password with the intercom next to the door to start the quest.

-> Being sent by Mr. House to learn about the Brotherhood of Steel. When entering the bunker from the northern entrance, a patrol will run out. This will cause the door to open, allowing you to enter.

-> Getting far enough in any factions storyline to be asked to find the Brotherhood of Steel.

-> Having Veronica as a companion, which allows you to use the intercom to open the gate.

-> After a getting two playbacks from ED-E, eventually a Brotherhood Knight manages to jack in to ED-E's comms, asking you to find a Brotherhood patrol so they can have a look at ED-E's databanks.

After the second door opens, you will encounter Senior Paladin Ramos, who will confiscate your gear and lead you to The Elder, who begins this quest. Note: The Paladin Ramos will shoot at the PC if he's dressed as an NCR troop, and removing the outfit will not cause Paladin Ramos to stop engaging the player. You're allowed to enter with your things if you got into the bunker via Veronica.

The Elder will start you off by telling you that he does not trust you and fits you with an explosive collar, designed to go off if you wander too far from the Brotherhood bunker. He then tells you a certain NCR ranger has set up shop nearby and wants you to oust him from his post. Once you have dealt with the ranger, he rewards you by taking the collar off and giving you the next part of the quest:
 * Note: If entry is gained with Veronica as a companion you will not have to do the ranger hunt below:

To locate several patrols that have gone missing, and to bring them back, if they are still alive, and if they are not, to retrieve the mission holotapes that were given to them. Note: if Veronica is with you the Elder will not put the explosive colar on you and will skip to the search for the patrols. (Xbox 360 Confirmed)

The moment you exit the Elder's chamber, you confronted by Head Paladin Hardin who tells you that he believes the Elder's policy of keeping them isolated from the outside worls will be their doom, and wants you to help him oust Elder McNamara. He asks you to find out more about what leads to an Elder being replaced and tells you to update him on all the quests the Elder gives you. These are all marked as optional parts of the same quest.

There are three locations you go to find the holotapes. One is by Black Mountain where you will fight multiple centaurs and Moe (Tabitha's pet) in a radioactive ditch, where two dead paladins and the log lie. Another is at the REPCONN facility, where with a speech of 60, intelligence of 7, and luck of 7 you can bypass fighting the robots entirely. The last log involves finding the Boomers by dodging their artillery. Once you have made contact with them, you are free to roam around the surrounding area and find the two dead Paladins.

REPCONN Facility
Once in take the tour with the tour guide, once in the Planetarium go through the door to the left up the stairs and get the keycard. Go back to the initial room and go though the locked door using your keycard, go through the door to the second floor, once upstairs go to the first door on the left and you will find a terminal(very easy) beside a nikola tesla and you, hack the terminal and select the first option, this will allow you unlimited acces to the second floor, now find the door heading to the third floor and enter, A security bot will tell you that you have 30 seconds to leave, quickly go to the BoS paladins by the rubble and take the holodisc and leave.

Nellis Air Force Base
Follow the rock face to your left all the way to the gate, go through the conversations with the boomers and agree to help, once you exit fast travel to the base again, you should be right outside, the boomers will no longer fire at you, turn around and follow your quest marker to the paladins in the crater, grab the holodisc.

Black Mountain
Head right after exiting the BoS bunker to a hole in the fence, follow the trail and you should come up against 5-6 centaurs, including Moe, in a ditch, at the bottom of the ditch there will be two BoS paladins, grab the holodisc and head back to the bunker, give all three holodiscs to Mcnamara, (You can also talk to Head Paladin Hardin who will accept the holodiscs and use them as evidence to oust Mcnamara.)

Ousting McNamara
If you choose to help Hardin, he will prepare to confront McNamara, which will take a few ingame days. During this time you will not be able to talk to either of them. Doing so will also abruptly end the quest.

Head back to the Bunker after a while. Hardin will have changed into Elder robes once the transfer is complete, and there will be a new discussion topic, where you can ask him about joining the Brotherhood.

Scouts
Head to each scout and start a conversation, the first option should mention "Are the Bears still hunting?" choose this and you will recieve the scouts reports, once you've collected all three head back to Mcnamara to give them to him.

Fixing the Air Filtration system

 * Getting the HEPA Air Filters

Vault 22

The air filters are located in a sealed off room and to access it will require you to obtain a keycard and go through the sealed off cave.

Note: It is highly recommended you fix the elevator in this vault as it will make traveling much easier (~50 repair)

Firstly, navigate towards the fourth floor (commons area). Head into the large area and drop down to the level below. From here, find the door labeled as "Quarters," and go through it. An average lock is on this door, but can be bypassed by using the terminal in the Overseer's Office in the Commons Area/4th floor. A keycard is in the first room on the left full of vegetation and ~3 spore men. Look to the right of the room to find a shelf. The keycard is on the third shelf from the bottom.

When you have obtained the keycard, head back up to Level 3 (food production) and enter the room with a terminal and a door. You know you will have the right room if the door cannot be lockpicked and it asks you for a key. Go to the terminal to the left and unlock the door (only accessible after you have the keycard).

Once you enter the cave, take your first right and head down that path. You will eventually come to a wooden door labeled Oxygen Recycling, enter this door. From here, go to the lockers in the corner of the room and search through it for the HEPA filters.

Finally, go back into the cave and retrace your steps to go back to the food processing room. If you have fixed the elevator, go there and head back up to the entrance. If not, you will have to manually go back up.

 Vault 3

Upon entering the vault you will encounter a Fiend who asks your business inside the vault. If your speech is high enough, you may complete a speech check of 64, and she will be persuaded that you are a Great Khan selling the Fiends chems. Just follow the main halls and you will end up in the Fiend leader's room, you can sell him chems if you have any, or not. Either way, the (object) will be in a locker nearby and will not be considered "stolen" if you take it. If you cannot pass the speech check, then upon entering the vault head to the southern part of the map and lookfor the living quaters door. Then head left and and (after dodging some traps) enter the door titled Recreation area. after speaking with the ranger either convince him to go help you kill the fiend leader or just kill him for the maintenence room key. This is one of the more straight-forward vaults.

Bugs
Helping Hardin to take over the chapter and repairing the filtration system are intended to be mutually exclusive quests. You must pick one or the other, with Hardin's route being easier but resulting in less faction rep (the average player ending up at "accepted") and McNamara's being harder but leaving the average player at "liked." Note also that the quests following their transitions are completely different.

However, there is a bug that allows the player to seemingly complete both options. For this error state to occur, you must tell Hardin about the "Chain the Binds" but NOT tell him about McNamara's orders to find scouts/paladins/filtration parts. The player can then turn in the filtration parts, tell McNamara you've turned in the parts, and finally tell Hardin about the orders. This is the only order of events that works, as the "Chain that Binds" dialogue options disappear from Hardin after turning in the filtration parts.

This route generates more immediate XP, but leaves the two NPCs in an error state. They will, for the rest of the game, both only tell the player to come back later. This prevents you from continueing on to the next part in the chain.

Note that both legitimate options will result in a brief period wherein the player cannot speak to their elder of choice, but this does not mean that they're bugged - leave the cell and wait for a few days to ensure they've made the transition.