I was thinking of the hidden rooms as Safe rooms, places to hide for safty.
I can draw some pictures. In the Israel Jarusalim had hidden tonals for exscapeing, hidding and storing things you dont want others to find. Each group of people seems to have these kinds of rooms to hidding in or exscape. The catacoms are like those kinds of rooms...egypt has many plays with tonals and hidding places.
We have in the US. the underground railroad, many houses having hidden rooms, and plathes. AS well way befor that, the south, florida had the old plantations build with tonels and hidden rooms for exscaping the indian raides. The Jews where hidden away behind mirrors, big grandfather clocks, and like Anna FRank, was hidden away.
The bible talks about one of the churches of old where the people meat in starge shaped buildings, and caves.
Hugs!