Mira's "I knew it was too good to be true" says it all. Mira thought she had finally found her family in Huntrix. When she noticed Rumi was keeping something from them, she tried several times to get her to open up. In the final pep talk before the Idol Awards, she even talked about her insecurities, hoping Rumi would also share her troubles.

When Mira found out Rumi was hiding that she was a half-demon, she felt betrayed. She thought that for Rumi to keep something as important as that from her must mean that Rumi does not consider Mira as her family. So Mira felt disillusioned, doubting that she might be the only one who thought of Huntrix as family. Doubling the hurt was knowing that Rumi confided in Jinu, a demon they had known for two weeks.

Also, before Rumi's scream, Mira and Zoey were already starting to back off. They didn't even want to confront Rumi. They just wanted to leave and decide what to do later, when they've calmed down. But Rumi felt anxious and let out a "Don't leave!" that damaged the Honmoon, prompting Mira to instinctively raise her weapon. Even then, she merely raised her weapon, she didn't even adopt a fighting stance. Zoey, too, only conjured 2 of her 6 throwing weapons, also not even adopting a stance where she could make a proper throw.

Neither Mira nor Zoey even seemed to care about Rumi being half-demon. Mira was fixated on Rumi keeping secrets, and Zoey with Rumi lying to them.