Yes, get her at the Ep7 party. Toward the end of the episode she will text you asking for help where she thinks someone is following her.
EP8 is interesting on the Rio path as if you help her with the stalker problem at the dorm party her attitude does appear to change toward you (it is nice in a way and a victory for Rio fans).
Also at the end of Ep8 if everything else happens, she rearranges the furniture in your room as a bit of a tease (like a little kid would do when they like someone).... it is sweet in a way but what I think is also important is Heather says, "Be nice to her".
To me, that is pretty big. Rio has either already told Heather about MC or Heather has really good intuition that Rio likes MC.
Make my "Interlude" a full up Rio/MC episode

With good writing, Rio could be girlfriend material.