Found this youtube of a lady who can play the flute and beatbox at the same time. I was totally amazed how the beatboxing did not interfere with the actual flute playing. The timing must have been impeccable!
Afternote: As it turned out when I searched on the internet, she is not the only one capable of this feat but I must say, I liked hers rendition best.
Afternote2: The background looked like she was recording this from some residential home. Yet I cannot hear any ambient noise at all. The sound reduction is impressive too.