Well, I keep thinking it's strange the zombies let Skunkan get away.... but remember: they also let Hope get away when she fell out of the other tower (and was left blind).
Perhaps Tanya found a cure and used it on herself, Saul and even Hope. We all know they were not happy with Hope at the colony..... perhaps she was infected?

Maybe a long shot but there must be a reason for the zombies to leave such an easy "meal" like Skunkan and Hope....