Scene with the widow (SPOILERS)
Ducked out to use the bathroom about 2/3 of the way through the movie. Of course, I arrived back just in time to hear Elliot saying "and THAT'S how we beat him!" (or whatever it was he said).
So what was the big reveal? The only real change to his approach was to assume that everything he was seeing and hearing was a hallucination. Was that what he learned at the widow's place?