I suppose it is possible that the neck shot was after death which would explain the lack of bleeding.
Let's reconstruct 'that' scenario with the known facts...
During the autopsy, pathologist, Venezis, removed the bullet from the brain of Sheila (bullet PV/19). He linked this to the uppermost wound upon Sheila's neck. He said in layman's terms, that the bullet entered her body under the chin, up through the roof of her mouth and ended up inside her brain. Death was instantaneous...
OK, with death being instantaneous, why would any would be killer feel it was 'necessary to shoot her a second time, only this time shoot her 'diagonally' across the throat? I can't see how Sheila could have raised the rifle from its original position close to her body to enable that first fatal shot (PV/19) to penetrate into her brain that killed immediately, for the rifle to leap away from her body with her finger still on the trigger, to enable her to shoot herself again across her own neck. Cops at the scene, spoke about the possibility of 'recoil' having occurred to explain one shot having followed the other, but I doubt that very much. Since, in this 'reconstruction' both wounds wound be bleeding together, and there would surely have been a corresponding vertical flow of blood from the upper wound, that matched the vertical blood flow which accompanies the lower wound site...
How is it, that there is no 'verticle' flow of blood emanating from the upper wound, yet there 'is' from the lower wound site. Sheila can't have stood upright after she had already killed herself with the first shot, can she?