While others in the mind palace, even Moriarty, communicate with Sherlock, Mary stays completely silent, barely moving but still intimidating. The room of the mind palace in both cases is a hall similar to where we saw John running in A Study in Pink trying to find Sherlock and save his life. Mary does the opposite in first: she stops Sherlock from finding something to fight the shock, moreover, he imagines her shooting him again in his mind palace, wearing her wedding dress and her ring. For the later “encounter” Sherlock places her in an open space so he can walk round her and see all of her but deduces nothing but the word Liar. Her most sacred truth in his eyes has become a betrayal (already reflected in how she is dressed as a bride as she shoots him) and now Sherlock can’t see whether even the slightest details he deduced about her before are actually true.