In Philip Pullman's The Amber Spyglass, what is the best textual evidence to support the theme "people make great sacrifices for the ones they love"?

In order to fully appreciate the moment in Philip Pullman's The Amber Spyglass when Mrs. Coulter sacrifices herself for Lyra, a development that occurs in Chapter 31, it helps to be at least passingly familiar with the previous volumes in Pullman's Dark Materials trilogy. Among the novels' main characters is Mrs. Coulter, who, it is known, is Lyra's mother. Lyra, of course, is one of the trilogy's central protagonists, and a figure deliberately likened to the Biblical character Eve from the Book of Genesis, Pullman's story being inspired by the Bible while also constituting an indictment of organized religion's perversion and exploitation of that sacred text (Pullman's view). Throughout the story, Mrs. Coulter is depicted as an antagonist--an almost demonic figure representing the personification of evil. As The Amber Spyglass approaches its denouement, this personification of evil gives way to the maternal instincts that have long been sublimated by the imperative of insulating Lyra from the more nefarious influences that have sought her destruction. This, then, is the context in which the following passage from Chapter 31 takes place:

"The cry was torn from Lord Asriel, and with the snow leopard beside her, with a roaring in her ears, Lyra’s mother stood and found her footing and leapt with all her heart, to hurl herself against the angel and her dæmon and her dying lover, and seize those beating wings, and bear them all down together into the abyss." [page 409]

In this climactic scene, Mrs. Coulter is no longer "Mrs. Coulter." She is now "Lyra's mother," a significant transformational moment as Pullman's epic struggle nears its ending.
In a series of novels in which the two main protagonists, Lyra and Will, present optimal opportunities for self-sacrifice, it is Mrs. Coulter's ultimate sacrifice for her daughter that best exemplifies the theme of sacrificing one's life out of love for others.