The white-on-white of her new prison plays tricks on Naminé's mind. They're mostly small ones, such as warping the spindly shadows into servants; sharpening crayons into so many knives.
But it's mostly lingering 'fear', and not true insanity. That would be painting the walls-
"I'd like to think, Naminé, you'd do better than that"
-or answering to the shadow leaning against any overcast corner. He's so far in the angles of grey hood one of his eyes and fray his neck. But Zexion has told her- in his own way- he died like so, so it makes sense.
A blink and he leaves, as he always did, with an almost-warm smile before sinking into darker backgrounds.