He's used it himself a few times which is why he might've stalled that long until he hit the ground. In turn he has no idea what Zangetsu is capable of either. It's just not a thought he's registering right now.

His leg hits that sword hard with a large amount of force and Zangetsu can feel just how powerful it is. He was definitely trying to break his neck with one kick. He's not like his usual self that would draw out a fight to play with his prey. He's out to kill and as efficiently as possible.

In close range with his reflexes slowed he doesn't care if he gets caught. Go ahead, grab him. His grin will widen sharply as his other hand lifts to thrust forward into/through his chest. He'll snatch the first thing he's allowed to get his hands on whether it is a lung, a heart or bone. "So feisty."