Here is how I think it goes down. (Putting on my deerstalker and reaching for my magnifying glass.) I think there are four clues we can look at to determine what happens this episode.

1. CBS plainly states that someone takes a chance on airline tickets.

2. CBS also states that there is going to be a yield used.

3. U/J and M/G are seen together numberous times in London, but whenever R/A and R/K are shown, they are by themselves.

4. And what I consider the most important clue of all, Rob is doing the final roadblock that he is allowed to do.

Putting it together, I get this. The first clue at the mat directs teams to Abbey Road in London. Bunching occurs, and U/J, M/G, and R/K take a direct flight that leaves later, R/A take connecting flights that are not confirmed, and then reach London and Abbey Road first. This is early morning in London. The next clue is the detour, and it states that the options for the detour do not open until 9:30 or later. R/A go to the Sherlock Holmes museum and are forced to wait. Meanwhile, U/J and M/G, having had the lead in Turkey have better seats on the plane than R/K, get to Abbey Road next, not knowing that R/A have already been there. They decide to do the boats, and head off in that direction, also being forced to wait for it to open, and giving R/K a chance to catch up to them. Both detours open, with R/K still lagging behind a little. U/J, not realizing that R/A are even with them, gladly help M/G complete their detour, thinking they have the lead on them. They are then directed to the London eye, and head off in that direction. As they leave, R/K arrive to start their detour.

Meanwhile, R/A chose the more time-consuming detour, and fall behind the other teams. They get done and head for the Eye. R/K get done also, and make their way there. U/J and M/G leave the Eye first, and make it to the yield, where either one of those teams yield R/A, and then struggle with the Roadblock. R/A arrive, find that they are yielded, and watch the other teams do the Roadblock, and then gets past on the yield mat by R/K, putting them is last place. This is then where Rob decides that he must do the Roadblock to keep them in the race, even if it is his last one. U/J get done, followed by either R/K and M/G, and they are told to go to the pit stop. Rob, maybe pushing himself too hard, tries in vain to get done before someone else, (as he is shown in the vidcaps getting distraught very easily, and I don't think he is quitting either) but can't get in front of anybody, and R/A are last to the pit stop and eliminated.

Of course, there are many sticking points. R/A could breeze right through everything and get done first, forcing M/G to yield U/J after they received help from them at the detour. Thus the title quote, Gretchen explaining why they had to use they yield. Or U/J get to the yield, see two teams in front of them, and are forced to yield M/G.

But the thing that stands out most to me is that Rob is doing the Roadblock. I feel, that if they were in first, Amber would be doing it to equal out their totals. And also, if they were in first, they probably used the yield, as it is the last yield in the race, thereby buying themselves more time. But if Rob is doing the Roadblock, I really believe that R/A are on the verge of being eliminated.

BTW: Quitting a Roadblock I am almost positive counts in your total. 1. Rob had to first announce that he was doing the challenge. 2. Rob started eating the meat before he quit, and 3. he stated that he was quitting the Roadblock, another acknowledgement that he was doing a Roadblock. So yes, Rob can only do one more Roadblock at this point.

on tv guide is states teams must drive a double decker bus AND solve a mystery.....so whats going on???????????

Very good analysis. I could definitely see it happening this way, although of course there are a lot of other different ways it could happen too. But, it fits with the clips we have seen and with some of the spoilers we have. And I believe you are definitely right that the Roadblock Rob quit counts against him.

Another reason why Rob would have to do the roadblock could be that Amber doesn't know how to drive.