Instructions
Play the game until you encounter Rodrigo in the prison. Rodrigo is an ally to your character, and will automatically give you a lockpick in exchange for your lighter.
Return to any point in the game in which you encountered a simple lock (for example, the copy room in the military training facility).
Use the lockpick on the simple lock to break the lock and access anything inside (in the case of the copy room lock, you will receive handgun bullets).