A Brinks fire safe uses a dual-lock system consisting of a key and a numeric combination. To open the safe, you have to unlock the combination a specific way, then use the key.
Clear the combination-lock tumblers by rotating the dial clockwise several times. Set the dial to 0.
Turn the dial clockwise fully four times, and stop on the first number for the combination lock on the fifth turn of the dial.
Turn the dial counterclockwise fully two times, and stop on the second combination number at the third rotation.
Turn the dial clockwise one time past the third combination number, and stop at the number the second time around.
Turn the dial counterclockwise to the fourth combination number. Insert the key, and turn clockwise to unlock the safe.