[Wildcat!]

Something just occured to me. Simon has made it clear throught the competition, he wanted Diana, JLS, and Eoghan in the final. Now if you noticed, he criticized all 3 of them in the first performance, and said he was nervous for Diana.
I think its a strategy to get them safe. At this point of the competition, people will vote for their favorites multiple times, if they realise they are in danger, they start to panick. So by letting Alex and Ruth off the hook, it probably made some of their fans not vote as much. I think its a brilliant strategy by him.