Clever editing. It's the ol one two trick. An interviewer with a cameraman/woman. Then wide shots of the interviewer nodding taken later. Mixed in it looks like two cameras are there. I use that method a lot in home movies too. Also use a reaction shot to something that isn't even related to it. ie camera on man laughing to a comedian's joke about a hat. Then camera focused on comedian as he tells joke about a scarf. The shot of the man who earlier laughed at the hat joke is mixed in immediately after the scarf joke. Looks great. Looks like two cameras were there..