Now that i think about it... Rika does not die in the same way in chapter 2 and 3 @_@ so the reason Rika can't try and stop her fate is because it is not clear how she die... she will always die in that day though... and it seems like the killer is not the same person? @_@ don't think Shion killed her in chapter 3... quite the struggle Rika-chan is going through V-V