The Genius of Alfie Allen
That moment at the end of the beach fight scene when Theon falls on his knees and washes his bloodied face with sea water? It was not on the script. Nor was it something the director came up with. NOPE. It was a spontaneous thing Alfie did, according to director Jeremy Podeswa (from the 7x07 commentary).
It may seem like a trivial thing, but it really is not. It’s such a highly symbolic moment, and the fact that it happened showed how deep his understanding of Theon is. On an intuitive level.