Thought David is saying she walked. I've never said it.
However the evidence does show June was shot 5 times in bed. Then moved across the bedroom & back again. Then shot twice more.
Always assumed she crawled. But don't mind alternative sources.
I have read your thread post, and referred to it earlier in the thread.
If June was shot five times in bed, she's staying in bed - in my layman's opinion. Especially if she is shot in the head.
In view of the layout of the main bedroom, if Nevill is shot in or as he is getting out of bed, he will leave blood on the bed clothes and will either tackle Jeremy there and then, or Jeremy will block him, or both. Jeremy is in his way. And if Jeremy shoots him in the upper head region at this stage, you can multiple the probabilities that he is not making it out of that bedroom.
I don't find your scenario very plausible (which is not to say it isn't happen - I accept it is possible).