Hidden Valley depot key

 is a miscellaneous item in Fallout: New Vegas.

Characteristics
This Key unlocks the door underneath the brotherhood Gun salesman which gives passage to the brotherhood armory.

Location: Can be found in the Gun salesman's inventory. Pickpocketing is the only way to get to this key and even though you cannot get behind knight Torres, there is a way to be hidden to her while crouching infront of her.

To get to the door simply retrace your steps to main hallway of the brotherhood bunker and then go down the first stair you see. Then re-retrace your steps to officer Torres and you will find a doorway between the armory and the gunrange.

Using the key will give you acces to the room where office Torres is standing which holds a bunch of T-45D power armors and helmets, a plasma rifle, a laser rifle and a bunch of ammo of all diffrent sizes.

WARNING: This will affect your karma, as taking the items in the armory counts as stealing.