|Episodes||14.11 Damaged Goods|
It's a Ma'lak Box. Secured and warded. Once inside... nothing gets out, not even an archangel. Especially an archangel.
A Ma'lak Box is a specially warded container designed to trap and hold angels, including archangels. While there is lore on the Ma'lak Box they are apparently impossible to build without the proper instructions and warding magic.