A/N: Assuming the real Doctor dies and a young River is his killer.
Disclaimer: Never will be mine.
He looks down at his glowing hands, golden tendrils beginning to obscure his vision.
Funny how the universe works, he thinks, reflecting on that fateful day in the Library. They'd always had a kind of bittersweet symmetry, he and River. A mysterious summons accepted without question, and the sender ends up dead in a flash of light as the summoned is forced to watch helplessly alone.
He glances at her for only a moment and he instantly regrets doing so; never has he seen such pain twist the beautiful features of her face. He suddenly wishes he had told her more often. That she is beautiful. That he loves her. That she is his everything.
The searing heat of regeneration pierces his mind and briefly pulls his thoughts from River. He winces and braces himself, for he knows another blast is forthcoming. He closes his eyes and thinks only of her.
The shot echoes across the silent expanse of Utah desert. He collapses. He is gone. And she finally allows her tears to fall as she fires at the retreating figure of herself.