Yup, he forgot, as it seems. And I like that part of the storyline very much, I said I found the reactions of both characters very realistic. But still, it is a very much creepy scene if you imagine it from a first person view, pretending not knowing the events that predate it.
I think that sometimes Naija can be a frightening character. She's practically a dangerous predator. The beast form is good symbol of that aspect, that's why I liked a previous fanart depicting her as repulsive monster. Sometimes she does things, that are, let's just say, not too environmentally sensitive. One of the oddest scene's of the game is when you venture into the nest of Nautilus Prime, kill the big momma, and raise a little nautilus made orphan by your own actions.
I think, this lack of strict definiton of good and evil in the characters of Aquaria is an important element of the story. Think of the Creator, Naija's mom, Naija herself. Also, we are the most cruel predators of Earth, yet we don't like seeing ourselves like this. In the end, this duality of the characters becomes a sensitive description of the nature of humanity.
That is why I would hate if this aspect of Aquaria never got adressed. It's sure relaxing to view her as the cute little girl that she is, but the other aspects of her character are the things that make her really interesting, and not just another reincarnation of disney's little mermaid.