Hibiki and Lata have a weird friendship due to him being a first year when she is a second year. Hibiki will harass Lata for the fun of it like making him catch her and calling him Latte. But she still cares for him and is kind to since he is like the only person who knows she is a spy,
Lata is, essentially, harassed on the daily by Hibiki. He enjoys her company and sees her like a sort of weird but cool older cousin, but can't help but feel that there's more to what she shows UA. When he discovers she is a spy, he stays silent because a) he thinks no one will believe him for multiple reasons, and b) he fears the repercussions if he's right.