The odd thing about the marathon is that the judges usually eliminate people based on their overall season performance (despite what they say), so I was surprised to see the judges eliminated M&D so quickly. Typically in these marathon dances, even in the professional world, the judges are all very familar with the dancers and the pecking order is well established. The judges are more or less observing to see if a couple is moving up or down the pecking order, not coming up with isolated results based solely on what happens during the dance. It is the same in ice skating and other events that are subjectively judged. So for the judges to score a couple so low compared to their usual position means they must have been really bad.
I liked their response to the announcement (finally) that they were safe--happy, grateful, relieved, but not jumping all over the place like crazy people. I've been annoyed with Derek in the past but I like the 2012 Derek.