Commercials. We return to Wash at the helm. He hears gunfire through the CB and starts demanding that somebody give him the 10-whatever-the-number-for-violent-assault-is. Nobody answers.
On the cargo ship, Mal, Zoe, and River have heard the gunfire as well. Mal realizes that it came from the galley, where Jayne was. They head in that direction and run into Simon and Kaylee, who also heard the gun. Simon freaks when he sees River. She says she was "following the voices." Why do all mentally unstable people on Mutant Enemy shows talk exactly the same? It's like they're all internally tuned in to radio KRZY (your source for rambling, incomprehensible dialogue) and are just repeating the latest programming to us. Simon tells her that she should never leave the ship. Mal orders Simon to take care of River (and calls him "son").
But rather than taking her off the ship, Simon and River follow Zoe and Mal as they head up to the galley. There, they find a huge mess, and eventually an unharmed Jayne. Mal asks Jayne what he saw. Jayne says he didn't see anything because the guy came at him from behind. "Big though," he insists. Jayne thinks he may have successfully hit the guy. Simon observes that he did while looking at the floor. There's a blood trail. Mal follows it over to some fan duct, where we can hear somebody gasping. Mal pulls the vent off; the man who attacked Jayne is cowering in the duct, muttering nonsensically about "no mercy." Mal insists that there's mercy. There's lots of mercy. Then he leans in and punches the guy out. Heh. Mal pulls the little man out of the duct and onto the floor. "Oh yes. He's a beast," Simon dryly says to Jayne. "It's a wonder you're still alive." "He looked bigger when I couldn't see him," is Jayne's reasonable response.