[helpfulTroll]

I was really hoping it would be something more like, because there's a mechanical flaw that causes the clock to run slow, and it takes three minutes reach the belfry of the clock tower from, the street. This means that when the clock master notices that the clock is running on time, he has three minutes to reach the belfry, and set the clock forward three minutes, so that it never runs slow enough to make people late.

Or something like that.