So, the female protagonist is technically a hybrid. ?She is the beneficiary of hybrid vigor -- she exhibits desirable traits greater than the sum of the parent species -- genetic synergism. ?So the offspring of humans who are cross-bred with aliens results in ?uber-warriors, better fighters than any that can be bred within the species, homo sapiens.
What's in it for the aliens? ?What do they gain by cross-breeding with humans that they can't get by intrabreeding?
Are both species trying to breed a superior warrior hybrid?
And if so, why would the alien want to kill the protagonist? Get a sample of her blood, yes. ?Take her captive as a human guinea pig, yes, for further evaluation and testing for?their breeding program. ?But kill her outright? ?It seems to me she's too valuable of a specimen to wantonly kill.
It seems to me that the stakes for her is not her life directly or immediately -- but her freedom. ?Both species want to exploit her as a guinea pig for their own malevolent purposes.
I'm try to understand what the stakes are for both species, why they both want to get a hold of her. What her (involuntary) role is in their plots.
One thing I am fairly certain of is that there must be no uncertainty in the logline as to her parentage, her unique genetic makeup. ?The dramatic question is not whether she's a hybrid species but what she must do about being a hybrid species.