Zoro held the attack for X of time while you can see that the attack is continuing(you can see Kidd behind Zoro) around the supernova, then Law comes in. Zoro is heavily injured now, Luffy probably also took a lot of damage from that Kaido attack. If Zoro blocked aka ATE THE WHOLE ATTACK, then why would Law teleport him? You can actually see the attack going through Zoro's body and bleeding.
At the end it will be Kaido vs Luffy 1v1.