Very well spotted!  It looks like the "reflection" is on the camera side (I don't know how these things work), rather than being visible in real life - presumably deliberate if it's there twice.  A nice touch. 

I suppose it could be interpreted in any number of ways (it could even mean that there's two interpretations!).  It seems to me that he's hiding something there, putting on a front for Irene's benefit (and it does turn out later that he was hiding his true feelings for her).   She, on the other hand, isn't (as her face isn't reflected in the same way).   She isn't just playing the game at this point. 

I also wonder if it could possibly a reference to Irene mirroring Sherlock.  There is so much of that - her hair, the riding crop, wearing his clothes, etc.  In the second picture with two semi-Sherlock's framing Irene, it's almost like one of those three-way dressing table mirrors in reverse, with Sherlock now reflecting Irene.  Matching cheekbones!

I kind of like the transition idea too, especially as in the first picture the reflection is looking backward, while in the second it's looking forward (although we're behind it).
 

Last edited by Liberty (April 30, 2015 8:53 pm)

Interesting find. Like you said, the show has done great things with using reflections to enhance emotions and direct the audience to draw certain conclusions. I think in this case the reflections could be a lot of things. They could be being used to strengthen Sherlock's own self-reflection and self-confusion throughout the entire episode. Thanks for sharing this!