[He does understand. It feels that all he can do is repeat it - I understand, I understand - because it's such a unique hell. Eren is quiet for a long moment, eyes on the counter, where he idly raps his knuckles.

[At last, he speaks, voice quieter than it was a moment before.]

In most realities, when someone goes away, it means they're dead. You'll never see them again.

Here, returning to our true realities is the closest thing to death we know. But even that isn't necessarily permanent.

There's no telling when someone might appear right next to you again. Every moment you're looking over your shoulder, checking your phone. It would drive anyone insane.

Maruki. I'm sorry. [And, because he thinks he knows what the response will be:] That you had to go through it at all. It's Hell...