To quote directly from the book... "That was Jack and Maurice and Robert," said Ralph. "Aren't they having fun?"
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Jack and the hunters were suppose to watch the fire, but instead they went hunting. The fire went out and there was no signal, failing to signal the ship.
The hunters were responsible for keeping the signal fire lit but, they in Chapter 4 they let it burn out which destroyed an early survival because a ship went past.
The signal fire went out when Jack made Samneric leave the fire duty to go hunting. It also goes out when Samneric "see the beast".
Some of the hunters were in charge of the signal fire. The hunters thought it was more important to be hunting for food instead of wasting time watching a fire. So they let the fire go out, at the same time a ship passes by the island. Ralph notices that the fire is out and runs up the mountain to try to get it going quick again so they can be rescued. Ralph is furious to find out why the fire went out and it starts a fight between him and Jack. :)
Jack Kevorkian went by Doctor Death, and Jack The Dripper.