/Ok. I've spent to much time trying in the section after you find the fan. There is one place where a bridge is blocking the door until you press the button under the bridge. But it seems to far to jump. Sorry not sure how else to explain it, but its after you find the fan, climb up, and head left. Help!
Edit: And of course after 30 minutes within 10 seconds of posting this, I figure it out. Well played!