In order:
The boots are clicking because they're traveling over the cracks between the sidewalk, and they have a bit of a heel... I don't really know, that's just what it sounded like to me.
Again, I'm not sure about the clicking, that's just how I described it. But also, when I was thinking about uniform clothing, I was thinking more as in jackets and pants. Thanks for pointing that out!
The elements are imprisoned as in they're in a city, all covered up by glass and steel, so there's not much "nature".
Bwa... sorry. That was a quick add, I wasn't thinking. I'll edit it...
The people were slowly peeling off, going to their houses... but she lived a bit further away.
It would cause him trouble because people aren't really supposed to interact in the City. I don't know, it made sense to me...
Hmmmm... valid point there. I didn't really think of the lanes as part of the City, more as sort of an extra, outside section... I may have to fix that. I wrote this all in one go, without really thinking, so I should probably do some editing.
I used mainly passive because I sort of wanted it to be like an observed report... but I'll try to rethink that.
I capitalized He and She because I wanted to emphasize that people here have no individuality, are simply numbers. I'm hoping that came through...?

Anyway, thank you for the critique! Sorry for the epically long reply, but I'll do some more editing, so please check back. Thanks!