She groaned because she was troubled by this, but due to the soft seat and vibrating vehicle inviting her to sleep Aiko started off on her journey to the world of dreams before she was aware of it, zuruzuru, her body slipped until she fell onto Hajime’s lap.
Normally, he’d send her flying because it’s a hindrance, but because he felt it awkward to act rude toward Aiko, he hesitated over what to do, then he decided to leave her as is. After all, Hajime’s information was the main cause of Aiko’s sleep deprivation. So if it’s just this, he felt that it couldn’t be helped, as he displayed unusual generosity.