Horse Death

In an attic room, illuminated by large Velux window, in the roof of a tall building (four storeys or so). A serious fight is taking place, although I'm not sure what my involvement is in it. One of the opponents (or the main opponent) is mounted on a horse, and the beast stamps and bangs around the enclosed space, wild eyed and unnerved by its confinement. Suddenly the horse and rider are smashed through the window by some action of the conflict, and I am at the window just in time to see the horse scrabbling and terrified as it slides down the roof, its legs - useless in these conditions - thrashing around, dislodging some slates, then it drops out of site beyond the roof's edge. I realise that I can't bear to investigate its broken body at ground level.