User blog comment:HanataSanchou/Important Takeaways from Ch. 805/@comment-5869646-20151029170511

Law never cared about Kaido, his only real goal was taking down Doflamingo. He was prepared and expected to die for that cause, and probably sent his crew to Zou so they would be safe and not get dragged into his personal grudge.

I don't remember that Trebol thing, I'm pretty sure he only said that he couldn't leave two enemies for Luffy to deal with.