Round 1 – 1 shot and knife zombies, open door to elevator hallway for 500.
Round 2 – 2 shot and knife zombies, open elevator for 750.
Round 3 – take elevator down for 500, at this point you will need to clear the debris for 750 and clear the elevator debris for 750 as well as have weapons you feel good with. I would suggest using round 3 to buy the MX9.
Round 4 – shoot a couple bullets into the zombies then knife them, leave one alive. Rack up points to grab the spitfire as your second weapon and then once you can clear both sets of debris go to the elevator and finish the round. This is important because ending the round in the elevator will count as 1 round of your 5.
Round 5-8 – stand in the elevator and don’t leave. Switch between weapons and try to land head shots to conserve ammo. If you need to you can use your special weapon. Make sure on the dog round you let the last dog come in the elevator so you can reach the max ammo, you cannot leave the elevator to go out and get it.