[Had Ion's own answer ended with a follow-up question, perhaps Ion may have been able to guess what Luke had been struggling to say. Instead, he thinks it's his own answer that had upset Luke. And why wouldn't it? This topic is only a reminder of the fact that when Ion gets sent home, he'll be dead. And when Luke gets sent home, he'll have to watch him die. He may have told Luke the details of what happened, but hearing it and seeing it were such different things... not to mention the fact that Ion had left out the part where he had intended, wanted, to give his life for Tear's even before he started reading the Score.]

[There was no reason to burden Luke with this, right? Perhaps he shouldn't have answered that question. Perhaps he should have given an answer that would have simply side-stepped it. Or perhaps he shouldn't have risked bringing this topic up at all.]

[...but they were friends, weren't they? Sanji had told him before that friends were there for sharing those burdens. Would it be better for Luke to know how upset he truly was or for Luke to simply be upset that Ion was hiding something? And after promising they wouldn't hide things from each other anymore...]

...to be honest, I'm afraid to even consider it. What point would there be in wishing for something I can't have?

They already said it would be impossible, after all. For someone in my situation to return home... [They'd just go back to being dead.]