This may not work for you, . . . but it used to be our in home tactic.
My only son had his bedroom upstairs, . . . stairs beginning on ground floor 6 feet from my bedroom door, . . . with the front door and foyer between the two.
My son was instructed to go to the farthest corner of his bed, . . . over by his night stand, . . . and hunker ON TOP of the bed, . . . his hand gun covering the door to his room. He would stay there until he got the ALL CLEAR from me.
Granted, he was a teenager when we moved in, . . . which helped. But at least I KNEW where he was, . . . and would not direct rounds into that direction.
We never needed to use the tactic, . . . and he is married and gone, . . . but at least we had a plan. I even thought of some extra bullet proofing under that corner of his bed just in case, . . . but I never figured out how to do it until it was too late, . . . he got married and moved on.
Depending on the ages of your children, . . . perhaps something like that could be a starting point, . . .
May God bless,
If you can breathe, . . . thank God!
If you can read, . . . thank a teacher!
If you are reading this in English, . . . thank a Veteran!