Antigone, the protagonist of the story, is trying to honor her dead brother, Polyneices. Allowing him to rest by burying him. Even though Polyneices was declared a traitor of Thebes, because he lead an army in battle against the his homeland.
After Creon got word of how Polyneices was buried he sentenced Antigone to death. Only he felt guily of killing antigone, so he banished her to a cave with very little food to die on her own.
Parallel to Antigone, Piggy tries to stand for what is correct and reason with the groups of people in each book. What that looks like in each book is very different, but the intention is the same. Piggy and Antigone both pay the price of their life for trying to do what is right in their eyes. Therefore, Antigone and Lord of the Flies are both examples of freewill and the right to choose based on beliefs, knowing the penalties of death.
As Antigone is stealthfully traveling to Polyneices to bury him, she realizes the concequences waiting for her back in the kingdom of Thebes. That was only if they found out. She didn't care, she did it for her brother. She honored him despite his actions to betray Thebes.
In Lord of the Flies, Piggy has a moment of peripeteia when he is being th voice of reason and is pushed off the cliff and then killed "on accident" by Roger.