Factual error: When Elektra closes her cell phone on McCabe, a dial tone can be heard. Cell phones don't have dial tones. Even if they did, Elektra hung up, so nothing would be heard.
Revealing mistake: When Elektra attempts to resurrect dead Abby, you can see Abby's chest rising and falling.
Continuity mistake: When DeMarco lifts his glass to look at Elektra you can see there's no meniscus where the liquid hits the glass. When it cuts to a close-up of the glass there now is. (00:05:55)
Continuity mistake: In the last fight seen next to the well, the well is close behind Elektra, but when she gets hit backwards the camera cuts to a side view and the well and Electra are a lot farther apart.
Revealing mistake: When the young girl "dies", you can still see her blink and breathe.
Answer: She was a gifted prodigy of martial arts.
Purple_Girl