It was the unusual episode of “Mad Men” where women were at peril. Richard Speck was on the rampage against student nurses in Chicago and it was frightening everyone from Peggy to Sally.

Joan, for her part, was standing up against her husband, just back from the war, but unacceptably to her, volunteering to go back for another year.

And Don! Don did something so shocking that it made you rethink everything about him – and the series. [Spoiler ahead].

Having Don choke to death a former fling who insists on coming over and reigniting their passion had the potential to change “Mad Men” forever from a sharply observed period piece to a murder thriller. It was the kind of moment that hadn’t even happened on the preceding episode of “The Killing,” despite the title (and yes, I’m keeping up with that as well).

But it’s clear soon enough that it’s a fever dream, fed by seeing the woman in an elevator and having words with Megan over it before going home with a cold. But, waking in a pool of sweat, Don has learned a lesson and something about himself. He’d never threaten his new marriage with the kind of reckless behavior he used to revel in. And as the world burns around him, in riots and wars, Draper has grown up a bit.