Well, ha has an arrow sticking out of his arm, perhaps even chest, let's just say that it slowed him down since those arrows probably destabilize spiritual particles, or just absorb them, still would/could destabilize his reiatsu making him waver/slower.
It was an energy slash, the only people known to be capable of doing that are: Ichigo, Ishin, Urahara, Ginjou, although for me, it looked like an arrow first, until I saw a zan near Kisuke's face, perhaps it's 2 people and not one ?
Not a bad theory. Thinking Isshin and Ishida Senior?
Manga/Anime I read/have read/tried to read:
Full Metal Alchemist
Dragon Ball(Didn't like)
One Piece(Didn't like)
Katakayo Hitman Reborn(Didn't like)
Samurai Champloo(Didn't like)