If you mean Mel...
**Spoilers Don't read bellow if you don't want to know**
**Edit: Trying to push the actual spoiler stuff down so that it'll hide it unless someone clicks on it.**
If I remember correctly (It's been a while) during the freeze time scene in the girl's locker room or whatever, you have the option to unfreeze her. Do that. It'll let her know about your powers.