Maybe I'm mistaken, but I was under the impression that Sherlock had arranged for gas to spray into the room while he was messing around with lights and animal sounds etc and watching John over CCTV. If it really was happenstance with leaky gas pipes I'll... I'll just... be extremely disappointed because what the helllllll.

Also, just like I figured it was a cab driver in the first episode, I figured it was gas almost immediately in this episode. I didn't get Sherlock's manic glee when raiding the sugar bowl at first because... what the what? Why would it be in the sugar?

I really really want to like this show but between the casual rampant misogyny and the fact that, again, I AM SMARTER THAN SHERLOCK HOLMES WHAT IS UP WITH THAT I just don't know.