actually it doesnt matter what control you're using.. when you have set the arrow keys to steer/accelerate etc. you need to use shift+arrows to get'em working in F12 menu.
racing and hotlapping are two completely different things.. if you take your line like that in a close race you'll surely lose positions.. Anyhow the track layout is same for everyone.. maybe he gained 0.05 sec by using this extra "runway", but everyone's free to try the same trick until we get some wall to prevent it..