1. Pete Campbell is so busy living that L.A. life, he only heard of his father-in-law's heart attack in passing via a business associate. "Who knew he had a heart?" is ironic, of course, because while there are many dark personalities on Mad Men, Pete himself is the show's only card-carrying sociopath.
2. Bert Cooper force-feeds Don the harsh reality that his presence is parallel to that of "a dead man whose office he now inhabits." Not that Don needed reminding; Don's is haunted by the ghosts of Lane's failures (if not the man himself), and Cooper's words cut to the core of the once unshakable man's crisis.
3. Don's face upon hearing the news he was was working under Peggy is rivaled only by Peggy's face after he storms off.
4. "You're in charge, sweetheart." This statement says everything about Lou's intentions. Using Peggy as a pawn of humiliation against Don will likely end badly, but it makes for great TV along the way.
5. Subtext became text when Lloyd from the computer company says to Don, "These machines can be a metaphor for whatever is on people's minds." For Don, it's pretty obvious: He's struggling to find his purpose when the world is clearly moving on without him, but he still clings to a romantic notion of his value. "What man laid on his back counting stars and thought about a number?" he asks Lloyd, whose response answers not only this question, but sums up the 20th century. "He probably thought about going to the moon."
Image via AMC