I'd save Ellie. The world is only as important as the people closest to me and if 99% of people I don't know had to be sacrificed to save someone close to me, so be it, this will obviously never happen in my life so I don't fully know how I would react or end up making the decision but I know Ellie would not be a sacrificial lamb for the potential of a world that is already fucked, that's for sure. The fact that the cure is only a potential is also a strong reason I'd save Ellie. I wouldn't trust anyone who would say otherwise to be quite honest but at the end of the day, someone who could sacrifice Ellie without hesitation is the person who should have been chosen for the job in the first place, the black chick should have done it herself and if I were in Joels shoes I'd save ellie but it'd probably nag at me enough to drive me into a shell of a person afterward.
I'd pick the most logical choice.
The vaccine is al but guaranteed if you collect al the audio files: There is one that states that there have been a dozen of trials to extract a vaccine from someone who was immune. They all failed and there is no guarantee that extracting tissue from Ellie would. What is sure is that it will kill her. So the options boll down to sacrafice a Child for a small chance of extracting a cure and an even smaller chance to succesfully spread it a cross the country. Just imagine the monopolyposition in a world as scattered as the last of US if someone had a cure. No way that would get distributed fairly. Or to save a Child against her own wishes and believes. I would change the latter.
Save Ellie and hope she doesn't end up a lesbian. Growing up and becoming an adult, understanding how important she is, would probably be enough that even if she wasn't into dudes, she may be willing to 'do the deed' to procreate. Maybe if they were lucky they could find someone who could do in vitro fertilization? Either way I think trying to have a bunch of children and then doing whatever testing was necessary once they were old enough, to see if they were immune or not, would be the better way to go initially. If that didn't work, then Ellie could always decide to go all in and sacrifice herself at that point when the potential options have eventually run out.
BTW that Joel GIF is creepy AF. lol
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