im gunna explain a little more in depth the benefits of this strategy...
the way this works is that it prevents zombies from piling in front of you because of the fact that zombies only spawn in the room you are in, and the room before and after you, in theory if you run fast enough, you wouldn't even need to shoot to stay alive. of course it takes some skill to dodge zombies but unless you are a complete noob you should be okay...
camping like a noob like in most strategies is boring, requires everyone participating to be effective, will eventually get you trapped, and will decrease your skill making you a camper noob
the running strategy is better because:
1) you will never be out of ammo with access to every wall gun and the box
2) you can teleport easily without having to make crawlers to upgrade guns or as plan B
3) traps and turrets can and do help speed up the higher rounds
4) you wont get trapped like if you camp like a noob
5) you can last to significantly higher rounds as opposed to camping
also some tips:
1) at the start of rounds and after you kill off a lot of zombies RUN! because they will all spawn in again and if you stop, they will spawn in the room in front of you and cut you off
2) perks are more important than a good gun for this tactic, you can do this with a non-Paped ak74u until level 25 or so. juggernaut will save you alot, speed cola is really recommended since if you get caught reloading and you got cut off... you better hope you have skill, double tap IS important, it lets you kill a lot quicker
3) dont run different directions with your team mates, it will get 2 mobs on either side of you, STAY TOGETHER
the ak74 is really good until rd 25+, you have unlimited ammo and its a decent gun
the ray gun is good all the time, by the time you get to rd 30 nothing else will kill anything
the thunder gun is good for saving your buddies or getting you out of bad situations
lmgs generally become useless after round 20, too slow and take too long to kill
assault rifles are good until round 25 but they run out of ammo too fast
smg are really good since you can run fast, get points, and you can restock ammo for 5 of them
the crossbow is good even after rd 30