This episode takes place in 1901.
When George Crabtree (Johnny Harris) enters the darkened room where Yu Da (Daniel Park) is sitting he says "Toronto Police." Then he approaches the front of Yu Da and says "I'm George Crabtree, with the Toronto Constabulary." The first an obvious error as they did not refer to themselves as Toronto Police, although there are instances of them, including Murdoch (Yannick Bisson) saying it in season 1 episodes.