I’ve been staring at this all day. On one level it’s a simple allusion to the Don Draper / Dick Whitman dynamic, but more broadly it shows Don at the crossroads between domestic stability with his family, and the independent recklessness of his earlier, more hedonistic life style. The retreating Don is wearing a lighter suit, as he did years ago in the early sixties, when he was more of a rogue figure going against the establishment. Perhaps his domestication requires a certain complacency with the establishment, The Man, the people in charge, that he knows he would have rebelled against in his earlier life. Don is holding Megan’s cut off hand like as a weighty obligation. He would much rather be the fugitive on the run, beating the system rather than becoming the system.