The Importance of Beds?

Although Historically many scenes take place on Mad Men in generally with charcaters in some state of repose on a couch or bed . This weeks episode "Mystery Date" seemed to have the symbolism of a 'bed' running rampant .
* It is pointed out that In the 1966 Richard Speck murders in Chicago, the potential 9th victimCora (Corazon) Amurao, escaped because she managed to wiggle under a bed while Speck was out of the room with one of his victims -
* Don goes home to recover from his illness in a ned , where in his guilt ridden dream state he murders the image of an ex conquest and stuffs her under the bed.
* Sally is afraid to sleep in her bed after reading about the Chicago murders in the tabloid she fishes out of the trash.
* In the morning after being given half a seconal to survive the night Sally is seen sleeping under the couch where Henry Francis's creepy mother is also sleeping .
* After ditching her husband for choosing Vietnam over his family Joan is found lying in bed, dresseed and smiling with the baby and her mother.As if on a lilife raft adrift in the ocean.
* Megan awakes Don from his nightmare, washed in glowing angelic sunlight and tells him she has been in bed next to him all night although he doesn't recall.
* At her apartment, Peggy brings out some bedding to prepare the couch for her house guest, citing that her boyfriend has too many things piled on the spare bed. (There was a weird scene where she stares at her purse ,full of the money she rooked from Roger, and gets fearful to leave it there with the new secretary then checks herself and cleans up the, but thats a seperate issue.
* Roger is lying in his modern lounger in his office when he is interrupted by Pete Campbell.

So what is the symbolism or importance of "beds" in this episode????