Konayuki must have got the distance wrong; the Twin missed Shichika entirely, not even grazing his hair. He saw an opening, but as he raised his hand to counterattack, he knew that it was more than strong enough to leave her with a mortal wound, and thought twice at the final second.
Instead, he shot backwards.
This is harder than I thought!
Her monstrous strength was still a menace.

Katanagatari Omnibus 2, Page 242