Actually, I would be interested to see how this quest would go if we had a player who was a Rinzeite in our party. Assuming it's not Astral. With him, everything is clear anyway.
If we don't take into account my suicidal tendencies, I would role-play. A Rinzeite is a friend and comrade to another Rinzeite. It seems logical. Honestly, I don't see any alternatives. A Rinzeite cannot, in any way, go against his own kind. Even if he is not under mental control, it would be extremely illogical to behave otherwise.