[Ion stares at the page for a long while. Although it's not written, "I don't want to tell you" seems heavily implied.]

[But what is it he doesn't want to tell? Ion doesn't know if this is real or not. It could be about a friend, it could be about Luke, or it could very well just be a hypothetical situation for no particular reason.]

[Either way, the last thing he wants to do is badger Luke about his answer.]

I can understand that. It's difficult to tell people something when you know it would only hurt them. Perhaps especially if it's something important.