The step to the back was expected.  Almost typical.  But to do it again and suddenly appear in front of him was a bit of a shock.  However, Zhou was prepared to display another way of countering an attack from a zanpaktou.  Rather than try to do anything flashy, he simply allowed the full force of his reiatsu to flare up and stop the attack from doing any more than crease his skin.  "Another important lesson," Zhou said calmly, staring down at her.  "When two forces meet, the one that is stronger will repel that which is weaker.  You should be careful of such meetings."