Without any reference to the source material, this episode was okay. Psychological torture and madness has always been unsettling to me (shocker!), so I didn’t care for those parts in the show. Which was most of it.
The beginning I really enjoyed, with Sherlock and Watson using Mycroft’s ID to sneak on the base and fast talk their way through security. The tension was great and the story could have gone anywhere. Downhill for there though.
So, the biggest crime for me was that this did not match the source material in any meaningful way. On its own the development of the characters in the show was pretty good, and the story scary – so if that’s what they were going for it’s a win.