I'd be interested to know the order of recording last night - my guess is that, with so many couples, they did the elimination in one go, just breaking for the saved couples to leave the group, then did the interviews while the dance off was prepped. The guest artist & dance would have been recorded earlier, the judges bit as soon as they have the votes in (so after 21:10 - the judges just have time to change). But hopefully someone will spill the beans eventually.