Kill all zombies in Dead Zone | Chapter 3 - Where the Dead Live DI Riptide Guide
Last update: 11 May 2016
Enter the Dead Zone and go through the first building, carefully approaching the place where zombies are. Do like in previous main quest - attack from distance with molotovs or grenades.
But some of zombies will surely use stairs and reach you - but it should be only Walkers. At the end, eliminate a single Thug.