You find a good, grapefruit-sized rock, and raise it up above Katariki's head.
At that moment, he opens his eyes. Reflexively, he launches a bolt of magical force up at you. It strikes you in the chest, knocking you down.
You both scramble to your feet. Katariki looks around, and takes in his surroundings, and this new situation, with commendable rapidity.
Then he looks at you, and sees the hostility in your eyes. "It's like that, is it? Fine, I'll break your bones, and then I'll do the same to your Surgeon masters."
An aura of blue light surrounds his fingertips. You'll likely have just one chance to take him down.