Possibly the public. though the public can only choose who the system has got to the end.
Possibly the judges who have decided who had a better chance to get there.
Possibly the counting system. For example Rachel could have beaten Lisa by a million votes last week and could now lose to her by one tonight.
Similarly Rachel's 5 4 4 lead coming in from two dances and one public vote has now been negated by one mark from Craig.