are you sure?zoey also get jealous on the others route, when she sees the MC at the bonfire with camila and riona
First of all, at my rio-others route the MC is sitting pretty much alone at the bonfire, Rio and cammy are about 2 meters away.
And than Zoey looked at him. And MCs face is the same like he looked at her as she was in the train... its not very subtle here cause those pictures are following each other.
Her reaction... crying and running in the woods are always the same, but not the reason behind that.
If MC is happy with a girl in his arms, its jealousy or more like realization that she lost him.
If MC is sitting alone at the bonfire, he cleary doesnt look happy there. Not one bit. And its the same expression like when Zoey left him... seeing that, Zoey realises that she broke MCs heart. Which make her run away and cry, she is certainly not jealous about two girls sitting at the other end of the bonfire. That would be really strange.