So, a person is targeting M or KG. He is astonished to find them in one bed, and must kill both. More noise is made than he anticipated, he is unnerved and, going down the stairs, finds a male looking quizzically around, trying to figure out what the unusual sounds were. The killer obviously has to kill him, and maybe X has poked her head out too, and is prepared by that time to fight for her life. He leaves E where he killed him, while X ended up against the wall where the red substance leaked out.
Just a theory, not necessarily something I am pushing. I tend to put more faith in the earlier account from DM of someone being found out of the bedroom, and I put less faith in the coroner 's changing stories.
Jmo