Richard had decided he was fed up with life, and so planned to end it. Hyacinth returns home to find him downing a bottle of whisky. He also informs her that he'd had a bottle of pills beforehand. As he collapses, his arm also catches a knife lying on a table top and he begins to bleed heavily on the floor. Hyacinth freaks out and begins to shout, which gets the attention of the neighbours. Hyacinth's neighbours, Elizabeth and Emmett, rush in to see Hyacinth punching Richard in the stomach, in an attempt to make him throw up, because she wasn't sure what else to do in terms of his potential overdose.
The neighbours come in and try to get Hyacinth away from his body, not sure if she might have attacked Richard, and begin to form their own suspicions when she screams and lunges at them with the knife. Cue a struggle where Hyacinth somehow gets fatally stabbed by Elizabeth, dying in Elizabeth's arms.
Elizabeth laments upon this death and after some time passes, the end of this dream involves Elizabeth jumping off a cliff into the water below, trying to swim away to drown at sea.
...why couldn't that have been the final episode?