When I remodeled our last house I built a storm shelter in our closet.
I built a few engineered tornado shelters with a friend so I had a good idea what is involved. The ones we built were in garages.
They make perfect gun rooms BTW.
What are the walls made of. I have 2 options, in a closet in our master bedroom do one or in the garage I have a closet area in the back of the garage, open it up and place one in there. The indoor closet seems the best.