<p>Seeing Peyton look and seem human in the time jump plus Liv offering her an chance to live on Zombie Island which population is all Zombies. It's very obviously that she ate little part of Darcy's brain which gave her the death vision before Peyton return to her human status because just like anyother food and medince that brain had to pass through her system. I know Blaine sold Darcy's brain to some guy who didn't want be a zombie anymore, but he kept some pieces to himself since those other kids he had were intially recused from him by Major. </p>

<p>^ Ditto  </p>

<p>Peyton saw who the woman was though, so it couldn't have been Darcy's brain? I think it was the guy who helped capture the kids, the guy with the beard who helped Candy escape and shot Payton. Payton shot him back and I reckon Blaine gave her his brain. He was probably with Blaine when he killed Darcy. Peyton then got cured by Ravi who cured everyone else (those who wanted to be cured anyway) </p>

<p>I think this last theory is more likely. Darcy's brain was scheduled to be sold, which surely happened in the time frame between her death and Peyton turning zombie - consider that Blaine and Don E were looking for Ravi for several days until they managed to break into the safehouse. </p>