Why were all four kept to go on to the next level?

It seems unfair to me and my husband. They all had the same opportunities to make it through. Some danced really well and lost weight well others did not dance quite as well even though they lost weight. It just seems like the judges were hoping one of the bottom two would win and that was the only way they could keep that person on the show.

Please explain this to me.

I'm sure that this stuff isn't decided at the spur of the moment. They probably didn't want to end the happiness of seeing their loved ones with someone having to take the walk of shame.