I just found this play through. I have finished this game at least 4 times and really can't imagine any other ending. I go through the hospital and kill everyone in sight. The human race has been broken and it wasnt worth Ellies life to save it. Besides, how could they synthesize enough vaccine for the entire population? There was no electricity, no refrigeration, no way to transport the vaccine, no way to disperse the vaccine. The infected would still be there. The inhuman animals would kill for a vaccine, for the power it would give them. That's why the Fireflies wanted a vaccine. They would be the most powerful people on earth. It would cause endless wars and fighting. Nope, Ellie is worth more than that. Let the new world begin.