None of us matter to him. This isn't Angel reverting to Angelus. This is purely Angelus. He's never been Angel. He will leave a trail of bodies a mile long if we don't stop him. I'm not going to leave Angel to deal with that.
You knew him in Sunnydale, Willow. While I greatly respect your power, you weren't there for the things we went through together. We have always had the understanding that if it came down to it, we would kill Angelus.
If you became evil again, and there was every chance your death would be a temporary thing, would you rather the people you care about to risk their lives trying to save you, or would you want them to be prepared to kill you to stop you from hurting people? If you didn't even have the memory of them, for some reason or another, to even hope that they might be able to bring you back?