In the episode, A scandal in Belgravia, the woman drugs Sherlock in her apartment. In the drugged condition, it was shown that Sherlock solved the death of the hiker. Now the solution in his dream was unfolded by a friendly discussion with the woman.
We see Sherlock takes too much interest in the woman after recovering from the trauma. So what does the dream mean? Did Sherlock explain the mystery to the woman in the drugged condition? Or the woman whispered the explanation to Sherlock's ears when he was dizzy?