If any stray beam seeped through the cracks and was able to damage his diamond skin, I don't see how he wouldn't be left with searing burns or at least some kind of hint towards damage taken.

Now I also don't know how Corban would be able to quick-cast that defence in a mere milisecond, as a reaction to his sheath being blocked. Myron wasn't preparing a riposte, he was scouting for Corban's whereabouts and aiming his attack beforehand, only a fraction of a second after the sheath struck had Myron actually unleashed the attack he had been honing. I might agree to him quick-casting so that it's not a kill-shot, but I still don't see him being left unscathed if sparks could burn through his diamond skin.

Oh, and this aerogel coating, is it actual aerogel? From my knowledge, aerogel is a good heat insulator, but it's actually quite fragile and shatters under pressure... and there's a lot of pressure in that hyper beam.

EDIT: Also I just remembered an important point I had in my head about our earlier debate. It's not relevant now, but I gotta' get it off my chest. You stated that all kinetic energy isn't connected, whilst I said it was. I think my part of that argument stems from the idea that the earth rotates, so everything is always given motion, regardless of how insignificantly small. But now I have to take in to consideration that this is high tier, so we can just tell physics to fuck off, really.