Outside of throwing Luffy under the bus which I really don't see happening now that the endgame is building up, if ZKK happens I imagine it would be similar to an Enel situation where it's clear Kaido suffers a loss but instead of going into space carefree he would try to cause some mayhem in dragon form as a last resort ( e.g. blowing up Onigashima or attacking the capital directly) and then Zoro gets him.