who's the mystery person? Kenny? Lilly? or Krista?
I personally think it was Krista, because with Krista the last time you see her is when shes with that group that tried to rob her of all her supplies, the one that you can hit with the rock follows you and you feed him too a walker, the second one you see in the middle of the river bank and you ask him if Krista is still alive but before he can answer the old man gets swarmed on one side of the river bank and his son on the other. You don't see the last one until the preview when Clem says I thought you were dead. Kenny I can see making an appearance probably towards episode 4 maybe and Lilly could have made it but if you left her out on the road you see a walker chasing her but if she takes the RV then there is a better chance that she could have made it...im pretty positive though that its Krista.