This build is primarily made to have a major emphasis on outrunning the hordes that approach. If you have ever played Black Ops Zombies, that same basic principle applies here.
Prioritize any threats in front of your path of movement that will damage your health or speed and disregard any zombies behind you unless they get too close for comfort. (RUN AND GUN) & (HELLFIRE) work extremely well together and slingshot you while sustaining fire on top of the already established move speed cards you'll be running.
Best used with Karlee's TEC 9 for the initial levels when you don't have the build online yet, but can work with any character.