late response but you can get a handy from the doctor
Viewing post in Aren't Grim Reapers Supposed to be Scary? comments
I think you've just gotta choose to stay with her longer on the 2nd visit (after the part where you collapse, which is kind of like where the "common" route ends and picking a route starts). There are 4 h-scenes for now, and only the redhead twins require you to "decline" or be negative towards every other girl (and positive every time toward them) to get their scene.