A turn of events (unfinished)

when some one is panicking and facing a zombie after 12 years of the apocalypse, they bite the zombie in hope that it would hurt it. Instead, something else happens. The zombie falls to the floor and starts to fit. Foam starts to burst out of its mouth and it falls silent and doesn't move. Moments pass and suddenly the girl hears coughing and a man is sitting where the zombie was. The bite saved him. 'where am I ... what happened?'