"How do you work that one out, then?" John retorts, finally lifting his head to look at Sherlock. "You were fine going into the water for ages until that stupid, sodding dream. Christ Sherlock, you had to chain yourself to something and knock yourself out."

It isn't hard to imagine the terror Sherlock must have felt regaining consciousness under water. John has lived the reality of it, shacked down the bottom of a well on the Musgrave estate and at the mercy of the water rising up around his neck.

"You're different now. Of course it's going to bother you."