Sacred box that housed survivors (3)
I believe the answer is:
ark
I believe this clue is a double definition.
'sacred box' is the first definition.
(the Ark of the Covenant, holy chest in the Bible)
'that housed survivors' is the second definition.
(reference to Noah's Ark)
(Other definitions for ark that I've seen before include "Animal rescue transport" , "Noah's boat" , "Large vessel" , "Boat built to withstand great flood" , "The earliest vessel?" .)