This is better if you have 3-4 players but can be adapted to a solo strategy.

What you want to do first is get quick revive. Now you want to rack up as many points as you can.

Get to the elevator and go into the main part of the pentagon. Now you want to get perks and use the random box. When you have enough points, go to the pack a punch and pack a punch your weapons.

When you have got the pack a punched weapons let the doors open and start spraying them and shooting the zombies. Keep doing this and when the doors open throw a monkey and 2 grenades to kill the ones that stood the blast, and always always stick together!