Imagine that in this instant your power fails, its pitch black, and the house immediately fills with choking smoke.
Would you and your family get out? Would your smoke alarms warn you first? Can you find a key in the dark? do your children know where to go? Is there an alternative exit if the route to your front door is on fire? How about a phone (not electric?) a torch? could you put your hands on them instantly without wasting time feeling around?
We do have a plan. There is an emergency key taped to the bottom of a cabinet near the front door, which could be found my touch. My children know to leave mediately and meet at a tree near the front of the house. If they can't get out down the stairs, they know where the fire escape is, and that cupboard has emergency lighting. They know to leave the animals to me ( in practice I would leave the animals, most likely, but wouldn't ever tell DC that in advance, in case they try to reach them)
It isn't perfect, and still things could go wrong, but it is the best and simplist plan I can come up with. DC have known this escape plan since they sere preschool.