'Are you looking for this'
Just before the crucial scene in which the knife falls in the water, the husband is inspecting his knife. He seems to open it and take something out of it.
Later, when the hiker is looking for his knife and the husband lets it fall in the water, he is looking for something, and the husband says "Are you looking for this" and he shows him a small round object? What is it? Is it part of the knife? It looked like a pill or something? Anyone? Thanks!