Emotional Consequences of Broadcast Television - S6-E13
Trivia: In addition to being the final episode of the show, this is also the only episode to include harsh profanity, with two uses of the "f-word." The first was done as a joke by actor Jim Rash, who surprised the cast by saying the character Abed is "f***ed up" during a take. It was so unexpected and hilarious, they decided to just keep it in, as season six was produced for the internet and thus didn't need to cut around profanity. The second use of the word, by the character Britta, was written into the script, but meant to be bleeped out. However, as they decided to include Rash's adlib of the word, they decided not to bleep Britta's use of the word.
Answer: It was part of the plot that when the boiled yam was dropped it looked like it was stepped on (which it never was). So there was no way to tell the difference between the flesh being soft because it was boiled or because it was stepped on (in the show that is, I don't know if one could tell the difference in real life). Plus, the rest of the yam wasn't boiled, so there was no evidence the yam was sitting in boiling water.
Bishop73