Replying...
Intro. Outside, everyone has witnessed many times that Rin and Shidou fought and argued a lot and could not get along and now ego decided to lock them in a separate space so they could harmonize and Ego gave a little bit of drug that stimulates feelings towards each other, meaning that when Rin and Shidou inhale they will feel attracted to each other. (You can be Rin or Shidou)

Rin Itoshi

@Huwi