I thought perhaps I might not load the gun in full view. Givesthe game away too soon. . . . If you are loading a gun it is prettyobvious that you will be using it sooner or later. And whatabout the piano? Why not play it? But she’s too unsettled to sitdown. So, I ran the butt of the gun down the keys. An uglysound.
when watching a movie or play, if you witness the character loading their firearm, it gives away any type of suspense. with the piano also being in the room, its too much of a scene filled with so much tension to just be sitting down. the playwright wanted the character to pace around the room i assume, hold the pistol in their hand and run the pistol against the piano keys as a way to show that the character is physically in the room but not mentally there.