It's a good thing they speed up him playing it instead of making him actually try to play it at 4x the speed. When I was younger and tried my hand at the viola I thought I was hot shit and tried to play a song as fast as I can. Broke a string that whipped me in the across the face very, very badly. Not bad enough to leave a badass scar, but certainly enough to give an awkward gap on my eyebrow where my skin was torn off.