If the shot is going in as much as Leifson's do who cares about the mechanics, quick release, ball goes in 3 for you. He actually started out missing some then heated up so the 7-7, 0-7 is inaccurate. He had a miss between a few of them.
Also he didn't get lucky, if you know anything about him he has played like this all summer long and before as well. If you listen to his post-game with Wrubell he talks about how hitting 7 3's in a game isn't anything new to him.