Something interesting I just realized after playing through it again:
Regardless of the story, I'm still having an incredible time playing through this and trying to get the perfect run down.
Chapter 14 and chapter 19 seem to occur in the same place, as the lobby that you start off in is the same. However, in chapter 14 as the jacket guy, you end up going to the bottom of the map, whereas you go to the left and discover the janitors' operation as motorcycle dude.
Regardless of the story, I'm still having an incredible time playing through this and trying to get the perfect run down.