Rewatching this is seriously triggering my yuri glasses. Kumiko is such a hopeless dolt when it comes to Reina. I’m wondering if she developed some sort of serious “crush” on her in their encounter on middle school.
You know like when someone saved you when you tripped, allowing you to see that person in a new light. (like noticing that person’s reliability, strength, kindness, etc.)
Only this time substitute “tripping” with Kumiko’s “careless remark” and the new light that Kumiko showed is how invested and passionate Reina is. Considering how directionless and apathetic Kumiko is especially in the beginning, I think those are traits that she would admire above all.