I think you done so well to describe this little moment, the situation you found yourself in, and what it represented for you. It is funny how we can take something so small and get such a deep meaning form it to write about.
I like your ending, kind of hinting that the sound is so powerful, and has felt like it has been there so long, that it would be odd if it suddenly stopped. IT also reminded me that when things like this happen, loud noises such as the drilling, once it stops, your ears feel ringing with silence... you know what I mean. It is like they cannot believe the sound is over haha.