There are a couple of answers that comes to Han's mind and because it's Han we're talking about, they're mostly sarcastic ones. He has to believe that the eyebrow and the comment has to do with the fact that little brother does give a crap about what they may or may not be dumping into the ground.

Han reaches for his beer and purposefully kicks over one of their water buckets so that it tips over. He takes a sip of his drink and gives the water a chance to run out onto the ground. Then he picks it up and places it underneath the about to be open port that Josh is still holding.

"I question the 'planetness' of the Nexus, for the record."