The metal doors I have also have metal frames. I do not think anyone can slam or break the doors without tools, and a lot of noise. They open out and not in.
I also have a canister of Fox CS spray by the door. l disagree that such could not be well used even with twins. Windows are another matter, and if I were concerned I would get bars on them.
I think some of you are over reacting in your thinking. Get metal outside doors with metal frames, OC spray, and yes, I think a gun is also necessary for bulletproof safety.
Ecclesiastes 12:13 -CENSORED-¶Let us hear the conclusion of the whole matter: Fear God, and keep his commandments: for this is the whole duty of man.
14 -CENSORED-For God shall bring every work into judgment, with every secret thing, whether it be good, or whether it be evil.