The first ethical decision Kit makes is to jump overboard to rescue the child’s doll on page 8. This decision seems easy enough at first. The child drops the doll, and Kit dives in to retrieve it.
If we read carefully, we see that Kit actually jumps in mostly out of anger at not being listened to when she asks the captain to turn back. If someone had listened to her, she might have stopped to consider her actions. As it was, she condemns herself early because swimming was not considered appropriate behavior, and the colonists assume that any woman who can swim is a witch.
Although she does a nice thing for the child, Kit's temper gets her in trouble. She does not think about others, especially how Nat will react. He jumps in to save her, and is angry when he learns she can swim. This event thus has far-reaching effects for both of them.