User blog comment:JoePlay/The Avengers Battle Royale - The Cage Fight/@comment-4651179-20120429031529/@comment-4652104-20120429143500

According to this Wiki, after she absorbs enough power she becomes class 100+ So it does not happen at will. Also, both Thor and Iron Man are class 100+ at the start and have a host of other powers at their disposal. She'll beat Captain America, but that will be it for her in this contest.