Must more people die for Edmund?

"As for you," said the Witch, giving Edmund a stunning blow on the face as she re-mounted the sledge, "let that teach you to ask favour for spies and traitors. Drive on!" And Edmund for the first time in this story felt sorry for someone besides himself. It seemed so pitiful to think of those little stone figures sitting there all the silent days and all the dark nights, year after year, till the moss grew on them and at last even their faces crumbled away...

Can anything be done to save Edmund?"

"All shall be done," said Aslan. "But it may be harder than you think." And then he was silent again for some time.

As soon as they had breakfasted they all went out, and there they saw Aslan and Edmund walking together in the dewy grass, apart from the rest of the court. There is no need to tell you (and no one ever heard) what Aslan was saying, but it was a conversation which Edmund never forgot. As the others drew nearer Aslan turned to meet them, bringing Edmund with him.
"Here is your brother," he said, "and - there is no need to talk to him about what is past."

"You have a traitor there, Aslan," said the Witch. Of course everyone present knew that she meant Edmund. But Edmund had got past thinking about himself after all he'd been through and after the talk he'd had that morning. He just went on looking at Aslan. It didn't seem to matter what the Witch said.
"Well," said Aslan. "His offence was not against you."
"Have you forgotten the Deep Magic?" asked the Witch.
"Let us say I have forgotten it," answered Aslan gravely. "Tell us of this Deep Magic."
"Tell you?" said the Witch, her voice growing suddenly shriller. "Tell you what is written on that very Table of Stone which stands beside us? Tell you what is written in letters deep as a spear is long on the firestones on the Secret Hill? Tell you what is engraved on the sceptre of the Emperor-beyond-the-Sea? You at least know the Magic which the Emperor put into Narnia at the very beginning. You know that every traitor belongs to me as my lawful prey and that for every treachery I have a right to a kill."

"Fall back, all of you," said Aslan, "and I will talk to the Witch alone."

"It was all Edmund's doing, Aslan," Peter was saying. "We'd have been beaten if it hadn't been for him. The Witch was turning our troops into stone right and left. But nothing would stop him. He fought his way through three ogres to where she was just turning one of your leopards into a statue. And when he reached her he had sense to bring his sword smashing down on her wand instead of trying to go for her directly and simply getting made a statue himself for his pains. That was the mistake all the rest were making. Once her wand was broken we began to have some chance - if we hadn't lost so many already. He was terribly wounded. We must go and see him."

They found Edmund in charge of Mrs Beaver a little way back from the fighting line. He was covered with blood, his mouth was open, and his face a nasty green colour.
"Quick, Lucy," said Aslan.
And then, almost for the first time, Lucy remembered the precious cordial that had been given her for a Christmas present. Her hands trembled so much that she could hardly
undo the stopper, but she managed it in the end and poured a few drops into her brother's mouth.
"There are other people wounded," said Aslan while she was still looking eagerly into Edmund's pale face and wondering if the cordial would have any result.
"Yes, I know," said Lucy crossly. "Wait a minute."
"Daughter of Eve," said Aslan in a graver voice, "others also are at the point of death. Must more people die for Edmund?"