Yes, it is. You need to peek in on her after she's done showering. if you hang out in the washroom, doing stuff like meditating or dancing until you no longer see Mio's silhouette in the shower, then peek in, she'll be sitting in the bath tub. However, I don't know if there's a heart requirement to be able to trigger the scene. There's actually 2 different versions of this scene depending on whether you grab the rubber duck in adventure mode. You should take a look at the unofficial guide for this game, it helped me out a lot with certain things. while it's not perfect, it's still very helpful to have on hand. Here's the link https://docs.google.com/spreadsheets/u/0/d/1fDTga-dhWarmZjoPLGN9X85UqCQwDj1L9NpI...