Many people have noted that the stairs in Sherlock’s mind palace in HLV bear a striking resemblance to the stairs in ASiP, from Sherlock & John’s first case/night together.
However there’s an added symbolism that I haven’t seen anybody comment on before. (Though of course I may have missed it! But this meta was the only thing I could find that covers similar ground.)
One of the biggest obstacles to John and Sherlock’s relationship is John’s disbelief in the strength of Sherlock’s feelings for him. And why wouldn’t he disbelieve? Sherlock has been pushing John away for a long time, has been careless with his time and his belongings and his emotions, has lied and experimented on him and called him an idiot. He’s encouraged John’s mistaken belief that “he doesn’t feel things that way”.
These doubts are so deep seated that even as late as His Last Vow, after Sherlock has risked his life multiple times, spent two years in a dangerous undercover mission, and folded goddamn serviettes for him, John still asks, “But why would he care? He’s Sherlock. Who would he bother protecting?”
But Sherlock doesn’t do this from the very beginning. Until they go view Jennifer Wilson’s body together, Sherlock has been on his best behavior. He smiles, he flirts, he offers to clean, he shows off his skills, he invites John on an adventure, he asks his opinion, and he defends John’s presence to Donovan and Lestrade.
The winds shift with this line: “What is it like in your funny little brains? It must be so boring!“ And then, a few moments later, Sherlock rushes out to find the pink suitcase… leaving John behind.
The music changes, back to John’s slow, sad theme. We see John slowly walking down the stairs, struggling with his limp, in a shot that takes nearly twenty seconds.
This moment, I’d argue, is the first time Sherlock hurts John. It’s also the first time Sherlock leaves John behind, but it won’t be the last.
It is therefore tremendously symbolic that this staircase is the one Sherlock struggles up as he struggles to survive the shooting. It works on multiple levels: he’s trying to get back to John, he doesn’t want to hurt or abandon John by dying, and in order to keep John safe and truly make him happy, he needs to address the pain and the distance he’s created – that he’s been creating since this moment, the day after they met.
