Not even sure what kind of scenario would provoke a reaction like that from Koishi. One idea that comes to mind would be this was in the past when they were being discriminated upon as mind-reading yо̄kai. Or maybe...
Kokoro was not satisfied with just beating the crap out of Koishi. She's coming for Satori too. Hopefully Okū would be able to cool her down.
Kokoro and Satori, huh... I do love the idea that Satori can "see" Kokoro's expressions.