Actually she doesn't seek vengeance, at no point does she actually seek vengeance in the film. She seek more of the drug, she seek understanding of what happening to her and she sort to share what she learned during her transformation to the one person who could have understood what was happening to her. She only ever harms people in the film that proposes a risk to her or tries to stop her from doing the above. Really if she wanted vengeance she could have just killed all the gangsters about 30 minutes into the film and let interpol take care of the mules but she didn't. In fact she showed little care for the gangsters or their actions throughout the whole film. She didn't even kill the person that put the drugs inside her in the first place, that white geezer.