I love this scene.  You wouldn’t think it could manage it, but it’s open to so much interpretation. XD  It sounds like John’s razzing Sherlock (which I love in itself).  

But I also sort of feel like that’s John’s restrained angry voice and he’s actually saying, “You got it wrong, it wasn’t under control, and you could’ve fucked me up severely.  Now admit that you only got lucky.”

And Sherlock does. <3  While looking faintly chastised, even.

Now if only I could figure out whether he meant, “I won’t screw with you again” or “I won’t be wrong again.” XD

It just occurred to me that I have no idea how much of a dose of the gas John got.  He caught a little in Dewer’s Hollow the first time, right?  And then there were both leaky pipes and a gas chamber at Baskerville.  And then at Dewer’s Hollow again, where this time John managed to be the steadiest person on the scene despite having been exposed the most besides poor Henry by then.  Apparently so long as he knows the killer mutant dogs are all in his head, the man’s basically unshakable.