I'm surprised I haven't seen anyone talking about the fact that it was John's idea to put the trace on the USB. John is usually left out of the planning and this time Sherlock told him first and they made plans on how to tell Mary and on how they would handle her reaction. John might have been hoping that she would stay and they'd take care of things together but he didn't trust her enough to take the chance that she wouldn't run so he suggested the trace.
I think it’s been brought up, but fandom moves so fast these days I wouldn’t be able to point you in the right direction. I LOVE that they worked together and confided in each other. And I’m kinda gutted we didn’t get to see it.














