User blog comment:Master Sima Yi/Assassinews 19-03-'14 – Two Assassin's Creeds for 2014?: Unity and Comet/@comment-4928711-20140612183744/@comment-5174994-20140612205140

Watching closer, it does look possible that he only grabs him on the neck. Although, I don't think we should rule out the possibility that there was a second.