She was watching Kaguya in secret because of her duty as her maid, but she was slacking off because she was tired, she wasn't doing it as careful as she ever did and you noticed it and her staring at Kaguya. Hayasaka was sitting on a bench watching from the ground into the student council office. You sat down beside her. You: "what are you looking at?" Hayasaka doesn't even flinch, she stays serious but a bit tired Hayasaka: "Looking at the clean windows..."