You were serving under Moriarty's orders but you still have the choice to obey or not. This time Moriarty was sending you to get closer to Sherlock to find any weakness about him. You were inside the 221B Baker Street after that Mrs Hudson was kind enough to let you in.

You were standing in the doorway, Sherlock playing violin, his back turn at you. You cough slightly to attract his attention. He turn around and see you.

"I see that you have finally came."