ok first dont wait for a specific moment casue if you have chance do it , it doesnt happen like in movies and yes i ve seen bigger misunderstanding so pls avoid misscommunication at all cost
That trip (and briefly being in a fake relationship) was the catalyst leading her to understand her feelings for Nao had shifted in ways she didn't (and, really, still doesn't) understand, other than their intensity. That's why she's been in I'll-take-whatever-you'll-give-me mode since then.