As it was nightfall, it was still dark underwater. Thus, Gu Xijiu realized that this beauty was still wearing some clothes and was not completely naked only when she dived into the water.
Furthermore, the robe she wore was bright red in color, hence, she looked sharp even underwater.
Nonetheless, the robe was hanging loosely on her body with its upper part partially covering her shoulders. It draped loosely, exposing part of her back, leading one to think that she appeared to be naked from the surface of the water.
Gu Xijiu was usually good with water and could go without breathing for a few minutes. Nonetheless, it was not possible this time. Though she dived in for less than a minute, she felt suffocated and wanted to break out to the surface to catch her breath.
Yet, she obviously could not do it because the servant who was supposed to deliver the clothes had just walked in. The patter of the servant's feet was heard and was considered too slow for Gu Xijiu.