Somehow, that was the one thing that never crossed Korra's mind. That someone else might have disappeared. Someone else who mattered as much to Billy as Naruto had to Korra — someone whose disappearance would break him, or at least send him a step closer to it. It makes guilt sink heavily in Korra's stomach. She's been through this. She should have known what his silence could have meant.

After Naruto disappeared, Korra wanted at once to scream and to also never speak to anyone again. And the inability to achieve both of those things at once was as jarring as anything else. No route towards being satisfied. Towards understanding.

She stands there dumbly, unsure what to say as she bounces Atka on her hip, a steady and instinctive motion. But her face says it all.

I'm so sorry.