Despite everything screaming at him to the contrary, Sherlock found that he did trust this fishman. The.. whatever it.. he.. was, had saved him. Why would he kill him now? It made no sense.

Sherlock got up on shaky legs and took a few steps into the ocean, almost to the rock but not quite. The water was a little warmer than the air outside in the cave (Sherlock could only hope that if he got out into the sun, it would be warmer there).

"I... can't breathe underwater." He said, making gasping noises. "I'll drown." He almost had once already today.