Everything
Leonel had been distracted by more than just his own weakness. After having been slapped nearly to death by the demon ape, Aina's white flexible armor had shattered as well. In fact, there was even less of it left than there was of her.
It was impossible for Leonel to focus on such a thing while the love of his life was at death's door. But after she was clear and her life was no longer in danger, if it wasn't for the weakness his body was experiencing and that he practically had no blood left to spare, he just might have experienced the feeling of his nose becoming a crimson geyser.
It was one thing to experience Aina's nakedness when their minds fused into one, but it was something else entirely when he could see it with his own eyes, and something even more difficult to ignore when she suddenly pressed up against him like this… especially since he had already retracted his own armor and there was nothing left on his torso but his own skin.