Disclaimer: I am running out of witty ones. Sorry.
She wonders how friends become enemies. That is the only thing that trickles through her mind when she is face to face with that lizard like creature—she refuses to think he is human. It makes her feel better, almost, the idea that she will die at the hands of a wild beast. Better that something distinctly non-human kills her, yes. That way, she need not try to feel any empathy for him.
How do friends become enemies? One moment, you are sitting with them, sharing a butterbeer or a cup of tea, and the next, you find the Dark Lord in your front yard.
He had looked so pale when last she saw him. He had been more jumpy than usual, although James told her that night that he had reportedly been put under the cruciatus curse (again).
She wonders why curse and cures have all the same letters, but mean utterly different things.
A curse is a friend who becomes an enemy. A cure is an enemy who becomes a friend.
A curse is your husband dying to save you. A cure is knowing you will be with him soon.
A curse is knowing that your first best friend is a Death Eater. A cure is knowing that he was not the one who betrayed you.
A curse is Peter Pettigrew. There is no cure.
Her mother was right. You can never tell what will happen in your life, how the people you meet can change your life forever.
One moment, you are leaning on your husband's shoulder, humming Mozart to your son, while your husband sends bubbles out of the end of his wand in rhythm with the changing notes; the next moment, your husband is dead and you have your arms flung out, knowing that you can't protect your son, the little thing that sat in your womb for forty weeks and is now beginning to say words like "mama," "papa," "ki'y,"(kitty) and "boom" (broom).
You know that whatever desperate pleading comes from your mouth will not change anything. You know you are begging someone who has no human emotions to save the one thing you have left, to spare what you have lived for, and what you would die for. But you know it will make no difference.
In one moment, you will be dead. In another, so will he.
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AN: So, I think it is possible to be thinking more than one thing right before you die. I think your thoughts are scattered. Granted, I have not died yet, so this is purely my imagination. I certainly think that most of Lily's final thoughts surround Harry, and her desperation for his survival. But I think there is a tiny part of her mind that is reflecting about what is causing her this emotional agony, and a larger part that knows it is no good. That's how this appeared.