Another goof up by Jin Yong?
When Cheung Mo Gei and little Yeung But Fui were en rout to Yeung Siu's home in the Kunlun Mountains after Gei Hiu Fu had been executed by her teacher Mit Jeut See Tai, they encountered that Gan guy and several others who had been healed by CMG after being poisoned/wounded by Granny Golden Flower. They were all in a famine-stricken zone where literally there wasn't so much as a blade of grass or a single leaf of a tree to eat in desperation. That's why Gan and the others were driven to resorting to cannibalism.
And yet, somehow, they were able to find ingredients for a "delicious broth" that Cheung Mo Gei spiked with poisonous mushrooms, killing his and YBF's captors and saving their own lives.
My question: if they're in a famine-stricken area with not a blade of grass to be eaten, how did they get ingredients for a "delicious broth," let alone poisonous mushrooms to be added to the mix?