Oh, you know! If they happen to get stuck in the water or something, you'll just go off and save them! You seem like a good swimmer so...w-why not?

[That and there was something else involved but no way she was going to mention it to him!

Nope, not at all! But based on her words, maybe he might get the idea of what she was talking about? Don't mind her laughing awkwardly once again!]