Oh, I know this video. I remember being able to play that “impossible” line
I’m sure that virtually every single bluegrass player can play that impossible passage.
Anyway, the lick you’re trying to perfect is not the same as what he speaks about here. The beginning of your lick has two notes on the first string and looks more like Yngwie’s arpeggios.
Actually, now that I thought about it, you could play most of it like Yngwie would: upstroke on e10, pull-off to e7, upstroke on b8, downstroke on g9 and the rest is alternate picking (except last four notes).
I think whatever approach you choose, seek for consistency in your technique.
Or perhaps you just trying to play it too fast. Synchronization could be your problem.
Some more experienced members might give you some better advice 
By the way, since you corrected me on that chord, could you be kind enough to write down other chords in that passage?
I’d like to learn this whole bit. Just write them in XX6777 fashion - it’s quick and easy.