Apart from the above doubts, if we follow this line of thought, it's possible that acquiring No. 6 Saint Delan Square was the result of the espionage organization's operations; and the detective's professed specialty in investigating mistresses and extramarital affairs could have been a deliberate choice to get close to nobles and eavesdrop on their secrets. His ultimate death might have been as a result of his efforts to fulfill the noble's commission, which would also corroborate Shard's conjecture.
However, if this idea is correct, then Detective Sparrow's mission could have been to lie in wait to be activated, or simply to infiltrate the upper echelons of Tobesk, or to join some event when the time was right. All of these possibilities vanished with the detective's unexpected death.
