The place I could not traverse is in the scene that starts at about 2:20. It doesn't look like much in the film (especially compared to the elevator shaft at first), but my legs just would not bend in the "correct" way to allow me down. Embarrassing, but true. Brad was kind enough to stay with me and make sure I made it OK (THANKS, Brad!).
From September 18, 2010: OLD MAN BY THE SEA ALTERNATE ROUTE