Youre half correct he was distracted because someone threw a lightsaber at him and he used his own to swat it away which is where the jedi takes his chance. Having said that we can see that the lightning is very linear even before he locks his weapons with it, there would have been nothing stopping him from doing the same thing he just did but then parrying the saber instead of standing there and watching his opponent slowly raise his weapon. That said, the point was just to show they've done similar manuevers in the franchise already
