True...but each department has it’s own compartment. Haven’t you ever watched AFN?
I don’t know what AFN is.
But I don’t know that the originator of SCI defines the extent of the Compartment...specifically who can have access. And those persons could be in ANY department depending on their need to know.
And, that compartment could also be limited to a specific unit within a specific department...like Naval Special Warfare Command. Or Cincpacflt...or...