Well, I just re-watched this week's episode, and I have my own theory:
Niki (the alter-ego chick) doesn't really have a special power. The one with the special power, is her husband--whose power is to "hide" himself in other people. That's why she goes violent--because he's the violent one. Also, what I didn't catch the first 2 times I watched the episode, was that after she kicked Linderman's henchman in the elevator, she said "If you threaten OUR son again, I'll shove my heel through your head" (or however it went--but she definitely said "our" son). So, at that point she was D.L. (her husband). Pretty cool, if I'm right!