The thing is, more adept female fighters have died upto now, and she is still alive just because Kurono turns up to save her. One moment of her doing something on her own would have been good, instead the same situation develops always. She gets into trouble or is put in a troublesome situation, and Kurono gets her out.
That's an idea in a run-of-the-mills story, and feels out of place in Gantz.
Tae isn't a veteran of many missions. She hasn't done ANY missions!