Dust confirmed to have turned invisibility on.
It may be safer to send a legionnaire since tax collectors are non-replaceable, essential roles. I'm really surprised Waaagh went bye bye. I don't believe he said anything that betrayed himself. Sumi is sad.
As for Yayap, like fred said, I'd be extremely, extremely cautious. He's among the few to take a really unmovable stance, toward Sin (much like Nick towards Rome, though the comparison would probably make a lot of people angry. Sorry, future readers.) Whether that's reverse psychology (or as they call it here, WIFOM) or not, I have no idea. Any theories regarding that?