How long does it take for a house to explode after a gas leak from a gas stove?

We're really ******* scared. We're in her gazebo outside , and we keep hearing rumbling sounds from her house. When we went back inside , we smelt exhaust coming from the stove , and it smelled like exhaust from her kitchen to her living room . What do we do ? :c Is it really going to explode ? :c When my friends dad went down , he turned on the stove , it made a couple of clicks, and then a hugeee burst of flames when up . A ton of exhaust has been revealed today . What's gonna happen ?