When Neena questions the scientists about where everyone has gone, the good doctor callously brushes her aside. He then reveals a taser that is to be used on Neena until she starts displaying useful abilities that they can exploit in their quest to create the perfect killing machine.
After she blatantly defies the men she is “gifted” a kitten to keep her company. This is later revealed to be a ploy to use the kitten as leverage to get Domino to cooperate with their tests.
Domino #3 shows the young hero’s ability in action prior to her birthmark and she is able to save her pet kitten from being shocked to death by the twisted man. Her luck compels the man with allergies who is holding the cat to sneeze so hard that his face slams right into the taser.
The result is an angered doctor telling the guard to brand Domino’s face for being disobedient yet again. This reveals exactly how she got her “birthmark” which in fact is a pretty horrible scar and a reminder of her dark past.