Hidden Valley depot key

 is a miscellaneous item in Fallout: New Vegas.

Characteristics
This key unlocks the door underneath the Brotherhood´s armory salesman Knight Torres.

Location
You can use the stairs and walk under her through the underground path. It goes right to her area and you can remain directly behind her out of her sight and hidden.
 * Can be found in Knight Torres' 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.
 * Using a stealth boy is also a possibility