How do you get the cabbage scene?
You have to peek on Rika while she is bathing first. If you haven't done that, then every night go upstairs. If it doesn't trigger ("I hear showering"), then you can either go to sleep and try the next night, or do a round robin (enter your room, back to hallway, downstairs, back to hallway, end of hall, back to hallway). I got all three shower scenes that way, but never more than once scene per day. Something with the triggers doesn't seem to permit scenes to happen multiple times in a day.