Please forgive my ignorance, but on the rare occasions I've been in possession of a gun I've always held the pointy bit away from me. Might it be possible that wherever Sheila was, she was in a state of semiconsciousness which was overlooked, the gun was placed in a position commensurate with her having shot herself, her finger covering the trigger, as she started to regain consciousness her body tensed, maybe in an attempt to sit up and she involuntarily pulled the trigger?
Good morning April. If ever there was a " stage-managed" pic,,,it's the one where the rifle has been placed upon Sheila,with her hand in such a position as to make you think she shot herself.
No way,,could anyone lie in such a restful looking position after they've either shot themselves,or have been shot. The pain/impact of a close-range/contact shot,,,injury,, would leave an excruciating contorted expression on their face,,,unless she was drugged up to the hilt.
People who die in pain isn't a pretty sight,believe you me,,particularly if it's a sudden death.
On the other hand,as you pointed out,if she'd already have been in a state of semi-consciousness,,then the force of the second shot wouldn't have had the same effect as the first. So yes,,after the first injury,she would have been in a dazed state,,,but even then,I would fail to grasp at her being able to carry out a second shot to herself,and my own theory there is that she flopped onto her bed after that first shot,,,and it remains to be seen/heard who actually fired the second one,but it wasn't herself,,,as she'd have abandoned the rifle.