What are the thoughts of Jack when he sees the naval officer coming to rescue the boys?
In the final chapter, "Cry of the Hunters", Jack has lost his authority and Ralph has triumphed. When the naval officer asks, "Who's the boss here?" Ralph loudly replies, "I am."
Jack's actual thoughts are not given, but one can surmise them from what follows Ralph's declaration:
A little boy who wore the remains of an extraordinary black cap on his red hair and who carried the remains of a pair of spectacles at his waist, started forward, then changed his mind and stood still.
Jack probably was experiencing relief, humiliation, and resignation simultaneously. It was all over: life on the island, his role as "king", and the change in his status forever.
Even more important than Jack's thoughts are the fact that they are not given. The point of view abruptly shifts from that of a 12-year-old to that of an adult. Jack is seen not as a tribal chief, festooned as a god, but as a dirty little boy in a funny cap. Ralph needs "a nose-wipe and a good deal of ointment." Poor Percival can't remember his name. Jack's solitary action of stepping forward suggests that he may think of himself as chief, but his sudden indecision - and the sudden change of viewpoint - suggest that we readers are not supposed to focus on these grubby children, but on the actions of the starched officer and his waiting cruiser.