KeenGamer: “Your guide for getting through World War Z’s Challenge Mode this week alive. Each week the modifiers and mission change, but we’re here to give you some guidance and help you through. This week is a sneaky one, and it could catch you out if you’re not prepared, or ready to fight tooth and nail for your health.”
Source: N4G PC World War Z Challenge Mode Guide: Weak Medic, Fixer, And Slasher