The Ties That (Possibly Do Not) Bind
You may have forgotten, but the very first thing we see this season is Don's downstairs neighbor, Dr. Rosen, performing what appears to be CPR on an unknown man. Later in that same episode we are shown what looks to be the same scene, only this time we are given more information: The man whom he is trying to save is the building's doorman. We find out later he was actually dead for a few minutes and if it were not for the good doc it could have remained a permanent condition. Here's the thing -- I'm pretty sure these are two different scenes and the man Dr. Rosen looks like he's trying to save here is not the doorman. Here's why...
These shots come from the scene where we actually see Rosen working on the doorman. The photo above these is the very first shot of the same episode. Notice what's different? It's the ties. Now, I can't quite make out if the ties themselves are different, but they are definitely being worn in different ways. In the stills directly above this post his top button remains closed and the tie is knotted tight. But if you look at the shot above it (from the opening scene) his tie has been loosened and the top button is open. So if he is not trying to save the doorman in that shot, who could it be? My guess is that it's Don which means two things: 1. Everything that follows that shot has already happened just like Randall said and 2. It may not, like
Sunset Boulevard, be a tale told my a dead man, but it's quite possible it's about one at death's door.