SuperTux,
In AR11 episode 4, after 3 prior episodes completely in the lead, Rob and Amber had a problem with the Magellan DETOUR and lost time having to switch to the other DETOUR in Puntas Arenas. They were on the second plane, which put them "behind the 8 ball" along with Uchenna/Joyce and Charla/Mirna. At a transfer point by boat from Bahia Lapataia, Uchenna/Joyce and Rob/Amber were on the next-to-last boat. There was supposed to be 20 minutes before Charla/Mirna (the only team in the last boat) were sent. However, they arrived at the dock on Isla Redonda only 5 minutes behind the next-to-last boat. Maybe Charla and Mirna were a little lighter than the other 2 teams, but it looked like a deliberate mistake on the part of the person controlling the boat launches. The postal sorting ROADBLOCK at the Fin Del Mondo post office was to find either of 2 letters addressed to your team from one of the teams in its original season. Either Joyce or Uchenna aced this random task with almost total luck except for skill in sorting through mail. Mirna did very well also. It wasn't Rob's day and he finished well behind Mirna, so far behind that Rob/Amber had no chance at catching up to Charla/Mirna before the pit stop not far away on Isla Redonda.
If there were some way for Rob to guarantee survival in AR11 in the Bahia Lapataia and Isla Redonda areas, he and Amber would have done it. In fact, Amber had misdirected Charla/Mirna to guarantee that they would be on the last boat.
The chain of events in episode 4 led to the elimination of Rob and Amber. Not being on the first charter flight from Punta Arenas to Ushaia, getting to the dock in the next-to-last group and then the nature of the ROADBLOCK all helped to bring mighty Rob down.