Six's brain goes blank here as Luka offers a hand and asks for exactly what Six was baffled by being asked.

"I-- okay?" He answers, taking Luka's hand in both of his. With great confusion, he guides the Princess towards the door.

"I don't know how to ask this--" He sounds very confused, slowing as they near the door.

"Why can't you see?" If there's an etiquette to this, he doesn't know it. But he also doesn't know why Luka can't see. Everyone he knows can see.

Sorry Luka, at least the question sounds innocent rather than malicious.