Absolutely done in post, too much sound happening all at once. The panning gives it away too.
Based on the other stuff in this thread I'd guess Clarke did all the video, the intern recorded a bunch of extra noise, they did all the necessary pre-production in logic or something, and then threw the video and audio together after.
This kind of stuff is awesome, I love good audio work in videos.
How many people can do this kind of stuff around here? I'd love to learn.