I think the question is a bad one, because it doesn't tease out my opinion correctly. No matter what my philosophical beliefs are, i'd have to help, because in the west, if you just ignore some dumb roastie, you would be put in jail for not helping.
Assuming this was in a vacuum, and there was no repercussions for my actions, then it depends on my meta-ethical framework. My meta-ethical beliefs are constantly changing, but right now they are a threshold-deontologist. So it's some combination of rights-based ethics with some combination of utilitarianism.
And i'm a believer of negative rights and negative moral duties. So I think I have a moral duty not to torture and murder humans and animals. I think I have a duty not to enslave humans or animals. I think I have a duty not to needlessly harm humans or animals (this includes foids).
But I dont necessarily believe that I have a duty to help. For example, there are starving children in Africa, or some other 3rd world war-torn shithole, but I don't think its my duty to help them, because I didn't cause their suffering. I don't think it's my duty to adopt foster kids in a orphanage, because I'm not the chad who sired bastard children and left them to fend for themselves. I dont think I have a duty to help the needy, I just have a duty not to harm them or anyone else.
I don't think I would save her, because its not my moral duty, and I dont like her. I didn't cause her to drown. I'm not sure if would even call anyone, as I dont know if it's my duty to. Probably I would, even if in the vacuum, but im not sure.
