Before I start, I want to say that I think you could teach a course on this episode, and if I had the time I could probably write about it until my fingers fell off. But I'd like to keep them available for other things, so hopefully the following will suffice.
As we open, Don is hacking away, and at first I thought it was that smoker's cough of his that stops by every once in a while to remind us that even Don Draper, matinee idol even for those people who never go to the movies, is going to die someday. However, as he and Megan get on the SCDP elevator, Megan tells him he sounds terrible, adding, "You even look terrible." All props to the makeup department, because he does look sweaty and ashen, but still: Overruled. Megan playfully tells him she's going to stand at the other side of the car, and Don tells her fine, "If you think you'll be safe over there by yourself." I see he's not above using the news story we'll be hearing so much about as joke fodder. Seems a bit callous, but he does feel like death at the moment.
The elevator stops, and an attractive woman whose headlights happen to be on (nice to know the building's air-conditioning is in working order) boards and practically meows upon seeing Don, sidling up to him in a manner far more suited to the end of the day than the beginning and calling him "my bad penny." Oh, and said attractive woman also happens to be Mädchen Amick, who has popped up on many shows here and there over the years but will always be Shelley Johnson from Twin Peaks to me. She's still so pretty, too. Don tells "Andrea" that he'd like her to meet his WIFE Megan, and as subtle as that was I'm surprised he refrained from sticking his wedding ring in her face to punctuate the declaration.
Don then explains to Megan that Andrea is a freelance writer from "the old firm," which I guess means SC, although I admit I don't get the reluctance to say it. Megan unsmilingly tells Andrea that it's nice to meet her, the stiffness of her words possibly being the reason her posture goes even straighter than usual, and then it's Andrea's floor, and she can't wait to disembark, telling Megan it was nice to meet her without a word to Don, who, poor thing, seems to be coughing even harder with the embarrassment factor thrown in. When the door has fully closed, Megan whirls and asks how many times this is going to happen. He tries to tell her that it was six years ago, and being that it's Madison Avenue, they're going to "run into people," and Megan doesn't reply that him running into people is the root of the problem here, instead saying that there are places in town they could go where they'd run into people she worked with. Well, given how these two got together, that would be... also Madison Avenue. Really, it is hard to feel too bad for her, but I suppose she's entitled to sulk for a while, and she most definitely seems to agree.