The achievement 'Do You Even Exo' Requires you to Meele kill 10 zombies within 30 seconds which is relatively easy. Firstly there are 2 ways to go about this.
1. Insta Kill Bonus - the insta kill bonus or Hyper Damage I'm pretty sure it's called in AW, works just the same as it does in Waw, Black Ops & Black Ops 2 where it will kill any enemy with a single blow, getting one of these is the tricky part as it takes patience to get one to drop as they're random and you may get one with nearly no zombies left or with at the start of the round.
2. My method - my method is pretty simple, firstly you want to knife all 6 zombies that spawn on wave 1. Secondly, you will want to open up the yellow 'Main Hub' door [750 Credits] to the left of where you spawn then follow it up into a circle room. Next go to the right of the ramp and open up the 'Administration A' room [1000 Credits] then follow it along (3D Printer/MysteryBox will be to your right) and turn down a tunnel which has a sign above it saying 'CMorgue'. Once inside this room turn right then left and follow the stairs up to another room that will say 'DExoTesting' [1,2500 Credits]. By this point you should be on round 3 so kill a few zombies and get the little bit of cash you need to open it ASAP!. Now drop down once inside and turn around 180* and turn on the generator which will then allow you to acquire the Exo suit. Once you have it on just walk around this room and try herd the zombies into the center close to eachother. Once you can see 10 (or more) start punching them and you will unlock the achievement.
This achievement can be done on Xbox Live, Private Matches & Local. I will have a video up soon for those who would rather watch then read.