Continuity mistake: When the 7 go outside, Troy is talking to Shirley, he takes his toothpick out to say he's not an ambassador, but in the next shot the toothpick is back in his mouth.
Continuity mistake: After Jeff and Britta have had sex, when Britta is pointing her gun at Jeff, in shots behind Jeff she is holding the gun sideways, but in shots from behind Britta she is holding it straight.
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