| Quote #1
"I didn't have anything in mind, and well you know it," she snapped quietly. "But now I've seen what the Master did, I haven't got any choice. You're supposed to know about conscience, aren't you? How can I just go and sit in the library or somewhere and twiddle my thumbs, knowing what's going to happen? I don't intend to do that, I promise you." (1.59)
From the get-go Lyra displays a strong sense of moral duty. She can't just leave the study once she realizes that Lord Asriel's life is in danger.
| Quote #2
First thing in the morning she hastened down to the catacombs and restored the daemon-coins to their rightful places, and whispered "Sorry! Sorry!" to the skulls. (3.136)
When Lyra rearranges the daemon coins, she is haunted by a night-ghast (nightmare). We see that she apologizes immediately and is sorry for meddling.
| Quote #3
Lyra sobbed in terror.
Mrs. Coulter is a foil to Lyra in that she has absolutely no moral compass. Here she remorselessly inflicts cruel pain on her daughter.