The House Always Wins V

The House Always Wins V is a main quest

Synopsis
The Brotherhood of Steel is sure to oppose Mr. House's regime and they must be eliminated, no questions asked.

Option A: 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 one completed Still in the Dark. If the Courier did not oust McNamara as Elder, then Hardin will be the Head Paladin; if they 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 character may become vilified by the Brotherhood. The Courier can kill everyone in their path or sneak. Upon exiting, the bunker will explode. There is a chance that there will be 5 paladins waiting to kill the player character outside. However sometimes if one Fast Travels quick enough the paladins will not have time to spawn.
 * If Veronica is your companion, destroying the bunker may set the player character's reputation with the Brotherhood to Vilified, in which case she abandons the Courier as a companion and cannot be recruited again. If one has completed 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.
 * If you've favored Hardin, it is also possible to earn the reputation "Merciful Thug" without completing either of the other two quests. In this case, Veronica will also stay, although she will warn the player character about continuing to fight the Brotherhood.

Option B: 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 character must still kill the elder and his two guards themselves since there are no turrets in the elders' office.
 * If one wishes to avoid the Brotherhood quests by killing everyone, but still wish to keep Veronica as a follower, then they can do the following:
 * 1. Go to the bunker with Veronica. Hack the Turret Terminal (Hard). Turn them against "Brotherhood Personnel." Let the turrets kill off everybody.
 * 2. Dismiss Veronica.
 * 3. Successfully sneak kill (being "HIDDEN") anybody remaining on the first floor and everyone on the second floor. It is also possible to kill everyone without sneaking by using Stealth Boys; however, The Courier's murders cannot be witnessed by others. By doing this, one should gain no reputation towards the Brotherhood of Steel faction.

Quest stages
Part V

Bugs

 * When one has activated the self-destruct sequence in Part V, sometimes the door to leave the bunker will be locked. The player character 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 one has begun killing members of the Brotherhood and are vilified, some members will not attack the player character.
 * If one has any companions with you during Part V, they may die as a result of the explosion if they do not get out of the bunker in time. Station any companions one has with them 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.

Behind the scenes
There is an unused optional quest stage stating "Inform Mr. House that you've negotiated a peaceful solution with the Brotherhood." However, this stage is inaccessible in the final version of the game and it is impossible to convince Mr. House to spare the Brotherhood.

Commenting on this, Joshua Sawyer stated that this route was cut because it made no sense for Mr. House to spare the Brotherhood. He and John Gonzalez discussed the situation, and agreed that it would be in-character for Mr. House to not tolerate the Brotherhood. Additionally, it would be a more difficult and compelling choice for the player to make. Sawyer also stated that, after release, being tasked with killing the Brotherhood caused many players to lose their support for Mr. House.