You brought up a good point that made me think about this unpleasant scenario in a different way:
Of course, not everyone sleeps on their backs or stomachs (Rollings killed his victims by turning them around and stabbing through their backs). The coroner stated that all victims were stabbed in the upper chest; with one fatal wound at the end — IICR.
At the very least, the killer would have had to have enough light to see their sleeping or current positions in their beds and turn them on their backs to kill them the way the coroner stated— and it would have to be done in relatively quickly to avoid either completely waking the person, having the person fight back, and/or giving the victim time to yell out in alarm.
Also, I really do wonder how he made his way through the house and in the rooms and actually see and then murder the victims in darkness. I’ve thought about that a lot and I really don’t know and I definitely don’t think he turned on the lights.
*And to fix my typo in my previous post: I was a PIO: I am dyslexic.