Locked in the clock tower

The clock tower stairs are narrow and steep, with a single bulb on each landing. At the top is the clock room: a forest of brass gears ticking in the dark, a bench worn smooth, and the great glass face glowing with its numerals backward from in here, the whole Old Quarter spread out below.

Ambrose finishes winding the clock with a crank the size of a ship's wheel, claps you both on the shoulder, and heads for the stairs with a booming laugh. The door shuts. A key turns.

Ambrose: As the ancient saying goes, two people and one locked door make a conversation! Back in an hour. Possibly two. Ha!

His footsteps fade down the stairs. Lucien looks at the door, then at you, with the calm of a man who has known Ambrose for a very long time.

He invented that proverb on the stairs. I heard him practicing. ...Forgive me. I could ring someone, and someone would come. Or we could watch the city from the inside of a clock. I leave it entirely to you.