You do get to see inside the room in the Hawaii Five-O series finale "Woe to Wo Fat. The characters walk through the middle pair of glazed double pocket doors off the single-story loggia into the room below the double roof. You can see the fireplace to the left (90 degrees) of the double doors where it should be and the doors and window on the opposite wall that looks out to the seawall and the ocean. The ceiling is clearly flat, though with beams.eeyore wrote:Without being able to examine it up close it is hard to say for sure.
On a side note, most of the house has beamed ceilings, either flat as in this case and many others, or sloped as in the loggia that leads to this room. The ceiling is also sloped with beams in the large upstairs balcony and the porch leading from the driveway into the house. The sets used in MPI took this design cue and it was used frequently.
I think forum member Sam has posted video or pictures of this scene somwhere.