Can Sherlock be stuck in his mind palace?

Question

In The Abominable Bride, Sherlock spends most of the episode in his mind palace and re-creates the case of Emelia Ricoletti, (almost) exactly how it was. But there are dozens of independent people in his mind. Is he really creating consciousnesses in his brain, or how does that work?

Secondly, near the end, Moriarty says

Too deep, Sherlock, way too deep. Congratulations, you will be the first man in history to be buried in his own Mind Palace.

Could that actually have happened? Would he have died/gone into a permanent coma?

Answer 1

The real world equivalent would be more akin to a catatonic state than a coma. Coma is a physical state of severe unresponsiveness, eyes don't respond to light etc. Whereas catatonic people are unaware of some/all stimuli but display signs of being awake such as blinking or rambling to themselves and is associated with psychiatric illness a la Sherlock rather than a physical problem which comas are more commonly a result of. Someone catatonic may still swallow if something is put in their mouth and liquid added as the body would impulsively do this but a comatose person would not. Also hallucinations are commonly associated with mental illness and Sherlock is envisioning/ hallucinating real life people he knows or people who logically must have been present in the case, he's creating their actions based on his pre existing knowledge of these people so their actions do seem in character but their actual consciousness (minds) are not what's present rather Sherlock's assumed expectation of their actions.