The Doorway (1)mad Men : Season 6 Episode 1 Guide

The title refers to more than just physical entrances. It represents:

Don’s pitch for the Royal Hawaiian Hotel—a suit left on a beach leading into the ocean—is essentially a "doorway" to suicide. It’s one of his most brilliant but disturbing pitches because it reveals he no longer wants to sell a dream; he wants to sell an escape. The Doorway (1)Mad Men : Season 6 Episode 1

We see Peggy fully settled into her role at Cutler, Gleason & Chaough. She is now the one dealing with "the kids" and late-night crises, proving she has become the very person Don used to be. The title refers to more than just physical entrances