Ordinarily, a portent offers protection from the ravages of wind and weather. On the sea-bed, the ocean above protects this dome from wind and weather; the dome merely keeps out the water that would otherwise occupy the space. Variable permeability of the force field allows for air exchange or shower (and drainage) as needed.
A small disk seems attached to the top center of the dome. Two blankets have been placed on the floor of the dome, and an object resembling a small toaster oven sits off to the side. Various other bits of survival gear have been unpacked from the survival pack, left at the foot of the makeshift bed. One end of a hand-size cylinder casts a soft glow in the tiny space.