Why would you follow a random extra walking past extras out a door into the stock exchange?
The whole point of that scene is to show that the people in there aren't what they seem. Not the "business lady" walking into the room, not the "shoe shiner" not the "janitor", etc. etc.
Same tracking "shot" after she comes out of the elevator with Fox too.
It's funny how some of you will look for "deeper" meanings and explanations that aren't there, but something like a shot like that, while one of those stock guys are mentioning Bruce showing up at "her" party is nonsense.