SPOILER - Explosions

About 45 minutes in to the movie, the husband wants to light a cigarette by using the top burners of the stove in the kitchen. Because the burners produce a flame, that indicates that it is a gas stove and not an electric stove. The husband turns the handle for the first burner to release gas that should ignite when it comes in contact with the pilot light. However, no flame appears. But before he tries the second burner, notice that he never shuts off the gas for the first burner. The second burner does produce a flame that allows him to light the cigarette in his mouth.
As the wife is about to enter the kitchen, she asks her husband a question even though she can't see him. He quickly turns off the second burner to extinguish the flame and hides the lit cigarette behind his back as his wife enters and looks toward him. Unfortunately, his mouth is filled with smoke so he can't answer his wife's questions. She gets suspicious and asks him if he's been smoking. When she looks away for a moment, that allows him to exhale the smoke and dump the lit cigarette into the kitchen sink. A few seconds later, he leaves the kitchen forgetting that he never turned off the gas being released from the first burner.
Because this gas is both invisible and odorless, the husband and wife can't see nor smell it as it continues to be released from the first burner in to the kitchen. The scene changes to the bakery.
A couple of minutes later in the movie, the scene returns to the kitchen where the wife is about to turn on the toaster. Activating the toaster requires the closure of a switch, which can generate a momentary spark that was sufficient to ignite the gas-filled kitchen and explode the entire house.