When the Professor is first, explaining to Gilligan, Skipper & later the others about the possibility of natives being on the island & that they would likely be head hunters, they all seem shocked, sickened &:surprised at the possibility, even though they had faced head hunters prior to this in #1.23;"How To Be A Hero", #2.11;"Chain of Command & #3.10; "Topsy Turvy.
Before Gilligan has his nightmare and falls into the World War Two Japanese munitions pit, he hears the voices of the other castaways calling out his name and asking for help. It is odd that none of the others who had fallen in before try screaming for help. It would make logical sense that someone would have heard someone calling out since many of the castaways during the search were at the pit where the laundry rope had fallen down.
Whenever one of the castaways falls in the trap and "disappears", there is complete silence when their name is called out, yet when the Skipper falls in (the last of the six), suddenly Gilligan hears all their voices shouting from down below.
As the Professor and Mr. Howell are looking around in the middle of the night, Mr. Howell doesn't seem the least bit upset that his wife is still missing.