The hooded figure could have made him disappear for a one-on-one with Kairi. Or this portion takes place in her mind. KH has separated characters for plot reasons before. Just like with Sora vs Roxas. Riku was likely removed from the equation to get at Kairi alone. Or the scenes take place at different times.I don’t think I’ve really seen anyone mention this, but I wonder what happens to Riku during the course of this? I’d assume the scene with them together comes before the scene with Kairi and the hooded figure. Nomura, what did you do to our boy?