Yep ... more or less correct: a drug contained within the smoke triggered by foot pads which acted on subconscious fears. Neat. As was the H.O.U.N.D. acronym and Maggie password. The political allegiances are evident.
Increasingly you get a sense of how the scriptwriter(s) are thinking while writing via Sherlock's scroll through of possibilities. And there's a kind of connoisseur's pleasure in second guessing how the original is going to be played off or reimagined.
Maybe not quite as atmospheric being outside London and we're starting to get dangerously self-reflexive/self-regarding dialogue (Watson criticising Holmes for turning up his collar or is it Martin criticising Benedict etc.). Too much of that and it will disappear up its own fan club.
Never mind. On to the next.
And a new catch phrase to deploy:
Holmes: Not good?
Watson: Not good.
Plenty of occasions to use that spring to mind.