Chet Desmond and the Surveillance Footage

So this has intrigued me for a while and I have noticed people bring it up here and there but I have never really seen anyone incorporate this into a reading of the film or show.

In the surveillance footage in the Philadelphia offices we see three people. Cooper and Jeffries obviously appear. But then after Cooper and Cole review the footage to confirm Jeffries was at the office, Cole asks: "But where did he (Jeffries) go? And where is Chester Desmond?" As soon as Cole says this, a figure enters into the frame of the monitor showing the entrance to the office building. That figure is wearing an overcoat like Desmond's and has a very similar gait. This drives me nuts! I have wondered about the relationship between this, the doubling image of Cooper and time in the scene, and how it all could relate to the ring, red room and lodges and Chet Desmond's disappearance but haven't really gotten further than that. I haven't seen anyone expand on this and would love to know if anyone has an interpretation.