Hmm... It's interesting seeing Rubigo thinking that Zarhe's taking it too far after his previous speech and actions. I just thought I'd point it out, because maybe his mind is very different from what we've seen of him. 

EDIT: Re-reading further into the comic, I now realize that he acts much calmer within the next few pages. This adds on to my theory of possible bipolarity, but I really can't be sure, and will just have to wait and find out.