He can see that look and smiles back, still somewhat uncomfortable, fearing a relapse, but nonetheless happy to be returning to what feels right. Nell anxiously walks over to him and back to the door, whining and giving her tail a few interested wags.

"Alright, yes, I am ready. Look at the two of you, whining in eagerness at the door." His smile brightens and he leans over to kiss Watson briefly. He opens the door, or tries to, as Nell only moves enough to allow the door to open just slightly; once there is enough room, she hurries out, and Holmes follows.