Maybe it was a quick, emergency?, trip to pick up some Methadone.
I think they thought she would be dead Wed. nite. This way KE is gone, everyone else is alseep. They wake up and she is gone. But NOOOO...she fooled them...didnt they give her more of that sleeping stuff on Thur?
A good possibility I hadn't thought of. Something unusual motivated KE's departure or it seems she would have stayed. Fleeing the scene prior to Anna's AND Daniel's death makes me very suspicious of her.
So just before each death, KE flies 2500 miles away....gets a call and immediately flies back. Same script, different day.