He was exploring the grounds. He had read quite a bit in the library, and was now more familiar with a many things, but there were still a great many things that he did not understand, and River did not seem to understand them either. He did not understand why he could not remember his life before he had woken up in the woods. The books all seemed to indicate that he should have had one, by all accounts and purposes he should be 17. The best explanation was that he was suffering from amnesia, and he found that he did not like it very much.
Exploring helped him grow more comfortable with this strange place that he found himself - strange only because he did not understand it and it wasn't familiar to him, hence the exploration - and today he had chosen to explore the pool. He had donned a pair of swimming trunks that he had gotten when he had explored the town, and wandered out to where the pool was located, not precisely certain what he was going to do next, and found he was pleased when there was someone else present.
"Hello," he said, offering a wave when she surfaced. "I am Kyle. Are you swimming?" He assumed the answer was yes, but he wanted to make sure.