 Why did the Groacians hide the ship?
I've been tied up every off-duty hour since I got here—" "You can't offend the Groaci," Miss Meuhl said sharply. "You've been here on Groac for four years, Miss Meuhl. "The impossibility of access to outworlders. An elaborate one picked out in pinkish paint seemed to indicate the Groacian equivalent of a bar. A Groacian bartender was dispensing clay pots of alcoholic drink from the bar-pit at the center of the room. Retief backed, rounded a corner into a narrow alley-like passage, deserted, silent ... except for the following Groacian. Two Groaci wearing heavy eye-shields and elaborate crest ornaments indicative of rank rose as Retief entered the room.
 They were afraid to admit they knew where it was.
 To overthrow the government.  They wanted to hide the Terrestrials as long as they could.  They were afraid to admit they knew where it was.  They wanted to keep it for further research.