Oneword: Maze

Sherlock paused for a split second to reference his mental map outlining their route through the maze of London's back alleys and rooftops. It only took a moment to reference the landmarks surrounding them and make a quick and decisive turn down the dark alley next to the Italian restaurant. John trailed behind him, just barely keeping pace with Sherlock's wildly-flailing coattails as he tried to keep track of all the twists and turns and secret shortcuts they'd already taken that night, in hot pursuit of the sniper responsible for their client's recent widowing. Sherlock was certain he knew their quarry's eventual destination, as certainly as he knew every possible way to reach it faster.

John gave up on learning Sherlock's map, and simply focused on keeping up without a fatal misstep.