Not sure if this fits your description well enough, but it's the first thing I thought of when I read your post:
Hide a gun picture frame:
YouTube - Hide-A-Gun Picture Frame
Have it mounted/accessible near enough to the door and practice getting into it with speed.
One issue is that it doesn't lock, but in an emergency that would only slow you down. With kids around, I'd just use it when I came home for the evening and could keep an eye on it. Mount it high enough that kids can't easily get it - and never let them see it open, so they have no idea what it is. Keep it empty when you're not around.
Hide a gun picture frame:
YouTube - Hide-A-Gun Picture Frame
Have it mounted/accessible near enough to the door and practice getting into it with speed.
One issue is that it doesn't lock, but in an emergency that would only slow you down. With kids around, I'd just use it when I came home for the evening and could keep an eye on it. Mount it high enough that kids can't easily get it - and never let them see it open, so they have no idea what it is. Keep it empty when you're not around.