See my post. Unless there is easier access to second floor windows, the breach in this case is likely on the ground floor. As the parents and 9 year old are on the ground floor in close proximity, and probably close to the stairs leading to the second floor, having two armed (husband wife) snatch the 9 year old and move quickly upstairs, one point, one rearguard, in this scenario makes better sense. As opposed to two unarmed teens come down where they might run smack into badguys on the way there. If it were my kids at stake, what I posted would give all of them the best chance imo.