"And we found your wallet on this man they fished out of the Thames –" Holmes broke off suddenly as he gasped. "What's the matter?"
"What did he look like?"
"Young, tallish, blonde, blue eyes…what's wrong, Watson?"
"They had me treat him for an infection, Holmes," he answered softly. "Left me alone with him…I convinced him to run from the gang once he could. He promised to tell the police or you where I was."
Holmes winced, wishing he had known this before he began.
"They killed him, because he was helping me," Watson whispered, closing his eyes for a moment. When they opened again, Holmes cringed to see them dim with grief-stricken tears.
Holmes grasped his friend's shoulder. "More likely they realized he was not an asset and were going to execute him anyway; had they killed him for aiding you, they would not have left your wallet in his pocket. You cannot blame yourself."
He was only half-convinced, but his head hurt too badly to argue with Holmes; he did not realize just how badly until he began coughing again. The room started spinning quite sickeningly, growing stiflingly warm.
"I'm sorry," he heard Holmes's anguished voice somewhere as he put a shaking hand to his head, trying to still the swaying ceiling. "This should have waited…blast you, Watson, breathe!"