I had honestly forgotten several things about this story from reading the manga a while back...
First, I had forgotten that Hiya has eyes that can open. From this point on she is one of the regular crew and I don't really remember her opening her eyes at all. So, I was a bit surprised that she was so expressive this episode. I guess coming face to face with mortality will elicit some feelings.
Second, I don't remember this bit about the hero becoming a monster at all. I am pretty blind on this part of the story as it does not fit with my memory of his character's story at all. I am not sure if that is because my memory is just bad, incomplete, or both.
Finally, a nice touch I noticed in this episode. While Flio and Rys are having a heart to heart on the bed, the gentle piano music playing in the background is actually playing the OP's melody that Rys sings. It was nice that it was a song all about how much she loves Flio while they are essentially becoming a husband and wife for real. I wanted to pick a screenshot from this sequence, but thought it might be a little spoilery, so I went with an angry Flio instead (@[email protected]):