Storm not taking a life wasn't a thing since Claremont even though some writers unfortunately like to vrevisit this when it regards Storm. Storm's perspective on taking a life all changed as a result as her them away from earth during brood saga. She was "rejected" by the earth and the elements upon her return which resulted in her powers displaying in an erratic manner. This would lead her to a more ruthless perspective which we saw when she killed Callisto.