Despite the concussion, it didn't take long for John to figure it out. No one could bring that mix of nervous energy and fascination and dread to Sherlock more potently then one man.

He slowly put down his cup of tea.

It was quite a good strategical move on Sherlock's part to stay planted by the door. Immediately, the doctor's expression went dark and icy, all soldier in the matter of a split second. No matter the irrationality--he had a recent blow to the head and a couple months of sorrow under his belt to justify it, after all--John strode forward, grabbing his gun off the bedside table, shoved it into the back of his jeans without hesitation and made to move past the other man and out the door.