What happened to Dr. Stanley in S01E06?

Question

During the course of The Terror Dr. Stanley is depicted as a largely arrogant and uninterested person without much emotional connection to either the expedition or the rest of the crew.

When Mr. Goodsir tells him about the lead poisoning from the canned provisions, he decides to not yet tell anyone about it (or simply didn't take Mr. Goodsir all too serious, like the rest of the time). When one of the crew members tells him about his depressions, he tells him not to worry about it too much and to enjoy the upcoming carneval as a distraction.

But then during the carneval in the episode "A Mercy" (S01E06), he suddenly sets fire to the entire camp and ultimately to himself, dying in the process and taking many crew members with him. This came entirely out of the blue to me for his character and I wonder what happened to him and why he completely lost it all of a sudden. Did he just despair at the situation they were in? Was there any kind of foreshadowing of this development of him that I might have missed?

Answer 1

The scene takes place in the episode titled "Mercy". So I interpreted it as him doing mercy on everyone including himself.

When one of the crew member comes to Dr. Stanley complaining of losing his mind and hallucinating, the doctor brushes it off with mental stress. Then when Goodsir informs him of lead poisoning due to eating canned food, he can connect the dots to that patient.

He doesn't want to die slowly and painfully due to lead poisoning and scurvy. He knows it's coming for him and everyone. Still he maintains a calm demeanor and pretends to not care about it. The calm before the storm. That can be interpreted as denial.

So basically, he sets himself and everyone on fire as a mercy rather than having to die painfully while losing your mind with hallucinations.

There was actually foreshadowing. When Goodsir wants to talk to Stanley, he asks "Where's the fire, Mr. Goodsir?"