Its clear from a number of pictures that most the blood loss from Sheila pooled in the right underarm area....
This area of pooled blood seemed to have dripped onto the carpet to give the distinct pattern found in the area by the right shoulder when her body was being carried and moved into position.
It's clear Sheila was moved... and in my view when she was being carried blood from the pooling in the right underarm area would drip...now if her right arm was dangling down when being moved it would drip onto her arm in several places...and run from there when her arm was placed across her when on the floor or similar.
This seems feasible and makes sense...though not ruling out other possibilities...I favour something like I have described.
I cannot agree with that. IMO, the blood you see on the photo would have formed this pattern by Sheila holding her hand to her wound - and I think she must have been sitting or standing still for some minutes. And it must be blood from the first wound.
In your scenario I think there would have been some splatter on the arm from where the drops fell. I don't see that.
Lets get a bit more scientific and think harder here...
You dont see blood splatter on the arm...
This may be because there was none...or the conditions were not right to produce observable splatter, or the picture quality is too poor to show minute splatter.
ok whats important for blood splatter
1/ velocity and mass of blood when striking a surface.
in the scenario I propose the blood drops will not be of large mass ... and the velocity if fairly low...the drops fall approx 10 to 12 inches (250cm to 300cm)...ie they are not travelling too fast...
think of physics and accelearation due to gravity...It is likely the drops were not falling fast enough to produce much or any observable splatter.
2/ instead of falling onto a hard surface the drops are falling onto the victims skin which is flexible and elastic rather than hard...this will absorb some of the drops impact...a small factor but critical for bloodsplatter.
3/ angle of the surface being struck... this is not going to be 90 degrees to the skin surface ... if there is splatter it will propel forward a little and then be covered by flow from where the drop landed. the lesser angle of impact means splatter will be minimal
4/ the drops were not falling onto an established pool of blood .
5/ the source of blood for the drips I envisage has pooled in the armpit area of the nightdress. This is blood that has been out of the body for a few minutes and will be a bit more viscous than fresh blood as it reacts with air making the drops less likely to splatter on impact.
SUMMING UP...
there is no reason to expect observable blood splatter for the scenario I proposed so the absence of observable blood splatter is no reason to reject that scenario.