The House Always Wins V

The House Always Wins V is a main quest in Fallout: New Vegas.

Quick walkthrough
Wipe out the Brotherhood of Steel by destroying its underground bunker. There is no alternative means of completing this quest without a mod. House vehemently despises the Brotherhood and will settle for nothing less.

The player must travel to Hidden Valley and enter the Brotherhood of Steel bunker. If the player has not interacted with the Brotherhood of Steel, they must complete an orientation by convincing a Ranger in an adjacent bunker to leave (if Veronica is a companion, the player can enter without the orientation). For details on this portion of the quest, please see Still in the Dark.

Once the player has access to the bunker, they may complete the mission by activating the self-destruct sequence, or by killing all Brotherhood personnel. Note that upon activating the self-destruct, the entire base will lockdown. The doors can only be opened with a Lockpick skill of 100 or by taking a key from either the guards protecting the Elder. The Brotherhood will also become hostile to you.

Option: Initiate bunker self-destruct sequence
In order to initiate the self-destruct sequence, the player must obtain the three keycards to arm it, or have a Science of 100. Assuming the former, the keycards are held by the Elder, the Head Paladin, and the Head Scribe. The Elder may either be McNamara or Hardin, depending on how you completed Still in the Dark. If you did not oust McNamara as Elder, then Hardin will be the Head Paladin; if you did, Ramos will now be Head Paladin. The Head Scribe will always be Taggart. The keycards must either be pickpocketed or taken off the corpses of the relevant individuals, though the latter may be difficult to achieve without turning the entire base hostile.

McNamara, Hardin, and Taggart are located on Level 2 of the bunker. McNamara and Hardin will either be in the meeting room or the adjacent quarters. Taggart is usually right by the self-destruct. Ramos can be found at the security station on Level 1 near the entrance if Hardin is Elder.

After the keycards have been obtained, the password for the self-destruct can be generated from the Override Code Generator terminal (green) next to the actual self-destruct terminal (blue). Once activated, the player becomes vilified by the Brotherhood. You can kill everyone in your path or sneak. Upon exiting, the bunker will explode. There is a chance that there will be 5 paladins waiting to kill the player outside. However sometimes if you Fast Travel quick enough the paladins will not have time to spawn.
 * If Veronica is your companion, destroying the bunker may set your reputation with the Brotherhood to Vilified, in which case she abandons you as a companion and cannot be recruited again. If you complete the quests Pistol Packing, Still in the Dark (favoring McNamara) and Eyesight to the Blind, this will earn enough positive favor with the Brotherhood for the reputation "Soft-Hearted Devil", and Veronica will stay.

Option: Kill all Brotherhood personnel
Killing all Brotherhood personnel in the bunker will also complete the objective. This path will lead to karma loss, as some of the named Brotherhood scribes and paladins are considered "good" non-player characters. However, this can be accomplished without a karma loss by hacking the turret control unit, and turning them against all Brotherhood personnel. However, the player must still kill the elder and his two guards "manually" since there are no turrets in the elders' office.

Journal entries
Part V

Bugs

 * When you have activated the self-destruct sequence in Part V, sometimes the door to leave the bunker will be locked. You must pick the lock with a level 100 lockpick skill, pickpocket the bunker key, or kill a person with the bunker key. On the latest patch, almost every Brotherhood member in Hidden Valley possesses the key.
 * During Part V, even if you've begun killing members of the Brotherhood and are vilified, some members will not attack you.
 * If you have any companions with you during Part V, they may die as a result of the explosion if they don't get out of the bunker in time. Station any companions you have with you outside before setting off the self-destruct, or be prepared to lose them.
 * Sometimes after assuming the role of Elder, Hardin will have neither key card, making it necessary to kill all BoS members if a science skill check of 100 can't be made.