I love the scene with Sherlock and Moriarty in Sherlock's mind palace. Andrew was absolutely freakin' awesome in that. "It's raining, it's pouring, Sherlock is boring. It's raining, I'm crying, Sherlock is dying." and his face when he calls Mary "that wife" of John's. Absolute love.
Also love Sherlock fighting his way up the stairs/back to life. The well placed slams of his fist, pulling himself up by the bannister, it all gives me the chills, it's so beautifully done!