It reminds me a bit about how Jefferson Hope went about getting his betrothed's ring back. He hired an actor to fool Holmes, to salvage what he knew he'd lost. He could (if he were a real criminal, and not a dummy for Holmes's deductions) gain more than only his ring back, if the actor also brought him valuable intelligence (or even incapacitated Holmes in some way). Would it be turning a sunk cost into a purchase, or am I mistaken?