Turn on the exhaust fan. Heat a 12-inch skillet or large wok over medium heat, put in the olive oil and bacon, and cook until the bacon is slightly browned and crisp, about 6 minutes. Using a slotted spoon, transfer the bacon to a plate lined with paper towels. Increase the heat to high and heat the pan for 20 seconds. If the bacon hasn't rendered much fat, add another 1 tablespoon oil and then add the shallot, garlic, and Brussels sprouts. Season well with salt and pepper and cook, stirring often, until the sprouts begin to brown, 3 to 4 minutes. Reduce the heat to medium low, carefully add the water (it will steam) and thyme, and cover the pan with the lid ajar. Cook until the sprouts are tender, about 5 minutes. (If the water evaporates before the sprouts are done, add more, 1 tablespoon at a time). Add the maple syrup, lemon juice, and reserved bacon. Swirl in the butter, season to taste with salt and pepper, and serve immediately.