BBC Sherlock: Nine Slices of Cake

In TSOT, clever Mary Morstan knew the boys needed "to run" and urged them to pick a case, especially Sherlock who was definitely becoming obsessive compulsive about the wedding plans. This fanfic occurs in that split-second when John convinces Sherlock to pick a case. Comically played by Benedict and Martin, this moment is IMHO a precursor to darker events to come in HLV