 Why was Retief still upset after seeing the ship?
"Whaffle left here three months ago," Retief said, "leaving me in charge." He looked at Retief and froze in mid-motion, a metal tube poised over a waiting pot. Retief backed into the opening to a narrow crossway and offered further verbal familiarities to the drunken local, who followed, furious. Retief backed, rounded a corner into a narrow alley-like passage, deserted, silent ... except for the following Groacian. "I can talk no more of this matter—" "You'll talk to me, or there'll be a task force here in five days to do the talking," Retief said.
 There was a much larger ship still unaccounted for.
 He found something at the ship he wasn't expecting.  The Groacians wouldn't show him inside of the ship.  There was a much larger ship still unaccounted for.  He's upset about the deceased Terrestrials he found.