Often when I isolate characters they can come across in a lonely way. I don’t think there is a sense of this here but she is sharing a moment with someone swimming, you just can’t see the character she is sharing a moment with.
After looking at this photograph afterwards, I realised it reminded me of my mum when I was younger. Whenever my sister and I would go to the leisure centre she would always refuse to swim. We always assumed this was because she didn’t want to get her hair wet.