OUT Sector is not really a sector. Rather, it's actually all the rest of the universe which is outside of Bubblegum Complex.
Much of it is wilderness, occupied by screaming mutants and animals, and the rest of it is home to the other Complexes.
Yes, that's right, other Complexes. Bubblegum Complex was just one of many created in the old days, and some of them survive. Some are run by commies. Some are run by Other Computers. And some...we just aren't sure.
There is no roof, and only a limited supply of walls. Many Clones find this very discomforting.
Despite this, a handful of High Clearance Recreation Resorts are maintained in OUT sector, for those clones cleared to know it exist and who like to get away from it all. Just watch out for Giant Mutant Cockroaches.