[The expression on Shun's face when Ren finally looks up isn't disappointment - it's still concern more than anything, and the rest is deeper thought. If the power can break through like that with so little prompting, Shun's first suggestion would be to be prepared for it, but that would require working with it, and Shun's pretty sure he knows the kind of reaction a suggestion like that would get.

As if to make sure Ren doesn't immediately look away again, or perhaps as a reassurance, Shun reaches up with his free hand to cup his jaw.]

Save your apologies. I'm more concerned about you right now. [And even if he's not going to outright make any suggestions, he...has to word his immediate thought in some capacity. It's said as gravely as ever, accentuating the fact that he's handling this with all the seriousness his information on it has led him to believe it requires.] ...Controlling something and not using it aren't always the same thing. I know you're afraid. I'll be there whenever you need it, whatever happens.

[More than anything, it's an offer of support, whether Ren chooses to consider his words or not. But looking at this, it's hard not to think the power is just controlling him in a different way now.]