If you have Veronica with you, then the Brotherhood will be happy to see you. Depending on when you enter the bunker, you might also find two grenade bouquets (hanging from the ceiling at the bottom of the staircase) or an NCR ranger named Dobson (during the quest If you don't want to take orders from the Brotherhood, then you can also kill them (some routes to the end of the game will even require this), but it's a good idea to complete their quests first, since the Brotherhood provides the easiest way to receive power armor training (the only other way is to complete the questīehind the 'average' locked door in this bunker, you'll find someīehind the 'easy' locked door in this bunker, you'll find someīehind the 'hard' locked door in this bunker, you'll find aĥ.56mm Rounds (in the debris to the left), and three ammunition boxes and a If you wander into their bunker (via Exit A) without Veronica, then they won't be happy to see you, and they'll force you to begin the quest Hidden Valley is the home of the Brotherhood of Steel.
