Sherlock faced the wall of the cell as the metal doors closed behind him and pressed a hand against the cold, painted brick. The spider on the other side was mirroring him exactly, pressing his cold hand to the same brick in the cell connected to the detective's, "Doofus," he said, in order to gain the other man's attention, pressing his forehead into the wall.
"Jim," he replied, forehead also resting delicately against the cell wall, followed promptly by the rest of his body. Chest, stomach, thighs pressing into the chilled brick as he spoke.
"Do you know how this has to end?" the spider asked, barely audible through the brick.
"I think I do," Sherlock answered, a strange sort of fear creeping into his voice. He wasn't entirely sure what Jim was getting at, he could only guess. That was a strange feeling for the detective, having to simply guess. It scared him that he couldn't read everything, that he couldn't feel what was going to happen, that he couldn't see his own future.
Jim chuckled, reading the fear and doubt through the wall, "Don't be afraid, little darling," he said, "It will be fun. Me and you, together."
Sherlock scoffed as he slid down the wall, finding a seat on the cold concrete floor. He leaned his head against the brick as he sighed, "That's not going to work," he said, "Think about John."
"Oh, I've thought about John and all your little friends. I don't think that will be much of a problem," he replied, smiling to himself as he followed the voice and took a seat on the concrete on his side of the wall. Tracing his finger lightly along the grout between the brick, he continued, "I've got everything so delicately planned, Sherly dear, we're going to have so much fun."
"You don't mean…," Sherlock trailed off, as the metal doors opened and he was escorted out into the hallway. He silently ran through the small conversation in his head, over and over, coming to no final or concrete solution. He joined John by the metal desk, ready to finish out the hearing.