I think this was how she’d end up back in the districts and then Ethan uses her as leverage against Cas in trying to kill him? Unless you want that to be a bit later on!
Cas will probably be a wreck when Iris is gone too. We should probably figure out how they'll reunite later xD Do you think she'll try to go back after she realizes Ethan lied to her? Or would it take more than that?
Iris would 100% try to go back to Cas once she knows Ethan has lied. I think we could probably have some fun with them reuniting in terms of drama too.