What are two emotions Jack feels after not killing the pig in Lord of the Flies?

At the end of the first chapter in Lord of the Flies, the three boys who are exploring the island come across a piglet "caught in a curtain of creepers." Jack, who has already proclaimed that he will take the role of hunter, raises his knife. However, he is unable to strike because taking the life of an animal is a fearfulthing. Indeed, as the pig escapes, "Jack's face was white under the freckles"...

At the end of the first chapter in Lord of the Flies, the three boys who are exploring the island come across a piglet "caught in a curtain of creepers." Jack, who has already proclaimed that he will take the role of hunter, raises his knife. However, he is unable to strike because taking the life of an animal is a fearful thing. Indeed, as the pig escapes, "Jack's face was white under the freckles" as he observes the "place of terror." It was not only the place of the pig's terror, but of the boys' terror, as they each imagined "what an enormity the downward stroke would be." 

Still, after he sheaths his knife, Jack shakes off the fear. Other emotions rush in. Like the other boys, he is ashamed that he was afraid to strike. His shame is certainly greater, because he has volunteered to lead the hunters, and because he was the one with the knife. He feels the need to make an excuse to hide his shame, saying he was looking for a place to put the knife. When Ralph and Simon ask him why he didn't cut the pig's throat, he has to walk ahead of them so they cannot see the shame on his face.

The second emotion that comes over him is self-recriminating regret. He realizes that if he had killed the pig, he would have established himself as a leader on the island. Had he single-handedly "brought home the bacon" to the other boys, how impressed they would have been! How willing to follow his lead and respect his authority! Now that the opportunity has passed, Jack kicks himself for spoiling his chance for recognition. He slams his knife into a tree trunk fiercely, as if to punctuate his anger at himself. "Next time there would be no mercy" on the pig, but also on himself. He will not let another opportunity to advance himself among the boys pass him by.