"This will go badly," John observed, standing on the landing, watching Sherlock test out his socks.

"Don't be absurd John."

John watched dubiously as Sherlock made a few practice runs, sliding down the hallway in his socks.

"You're going to get hurt."

Sherlock scoffed. "How could I get hurt? I'm wearing a helmet, wrist pads, knee pads, and these dreadful goggles."

John shrugged. The goggles did make him look rather silly, but there was no way he was going to inform Sherlock that. "I'm sure you'll find a way." He frowned. "Why are you doing this anyway?"

Sherlock rolled his eyes. "Science, John. Science."

"You said that before you singed our curtains and before you burned my hand with the acid," he pointed out. "Those didn't turn out well either."

Sherlock turned to glare at John. "If you are not going to be helpful, then go away."

John shrugged, and returned to his chair.

Better.

Sherlock took off for his slide, but managed to seriously miscalculate the angle, and instead , twisted his one foot under the other. He lay there for a moment, knowing that John had heard.

"John," he called.

There was silence for a moment, then a reply.

"What."

"I think my foot is broken."