Law being an asshole as usual.
At this point of the story, the way he treated Chopper is that of a garbage person. It's thanks to the Straw Hats that he could avenge Corazón. It's thanks to the Straw Hats that he had the drive to attack Kaidou. Chopper just risked his life as a doctor to cure Queen's virus which was a significant factor against their chances in the war. Plus many other things they shared since Punk Hazard.
I've always hated this side of Law. Earlier I could understand it, but at this point he's well aware he can't defeat the Straw Hats and he obviously won't fight to death, ever, since they are all friends. You can be a rival, of course, but no need to be a dick.