During the June 11th press conference, it was made clear that all of Negril is in the Corridor. There are certified properties in Negril that are technically outside the definition of the Corridor and you are allowed to stay there.
Note the wording, "The boundary only takes into consideration the main road to the sea shore." There are properties on the non-sea side of the road that are certified. The Corridor is guided by the boundary, but it extends to encompass the certified businesses around the boundaries.