Bank of England

1. The door has a combination lock on it.
2. The tumblers turn too quietly for you to hear without amplification.
3. Listen to the door with the stethoscope, and then turn the dial left or right.
4. A 'clunk' means you're going the wrong way.
5. A 'whirr' means you're going the right way.
6. A 'click' means you should reverse directions.
7. The combination is right twice, left once, right twice.