Before Lorelai's shoe breaks, and the board reads 6 couples remaining the guy in green and girl in the blue dress are eliminated when the man falls over. After, when Rory is dancing with Dean, the board still reads 6 remaining and the couple previously eliminated can be seen in the background.
Earlier in the episode, Rory says that Andrew always gets in a fight with his date within the first 15 minutes and storms off. Later, when Andrew starts yelling the girls say "right on time" but the clock says 6 hours have elapsed.