Black Ops: Zombies "FIVE" Tips/Strategy

I've been playing the crap out of the new COD Black Ops, and so far am impressed by the entire game. But, the one part I can't stop playing is Zombies. I stay in the Five map and have met a lot of people that play it a lot too. There are a lot of different strategies at trying to get as far as you can, but you Definately have to work as a team. If you have 1 selfish person that wants to go off on their own, it make for a short outing for your team. So far I have figured out that for the first few rounds you only need to use your knife or pistol to build up points, knifing gets you more points. After getting through those rounds knock down the door that leads to the next room, 750 pts, and grab a machine gun. Make sure that everyone has a position to kill the zombies coming from all directions; its best if all players have mics. After a couple rounds earning more pts you can unlock the elevator which will take you to the next room. This room has a wlkway upstairs that goes all the way around. You want to make sure everyone has a window and kill as many zombies as you can until you think your almost done with the round. Then some needs to create a "crawler". You can do this by throwing a grenade at a few zombies, if you see one crawling, DO NOT KILL HIM! This will allow you to look around and unlock things without being bombarded by tons of zombies. Next you will unlock a barrier taking you downstairs. You will want to head to the next elevator. Take it down to next room. This room contains the power switch and the so called mystery box. If you have plenty of pts, you can open doorways to different rooms to find the box. The mystery box costs 950 pts and will randomly give u a gun from a pistol to the ray gun. Make sure you all stay together because your crawler can die on its own and you do not want to be stuck all alone. The best thing to do is get on the elevator, make sure one person has the window and the other three unload on hoard about to invade you. If you get overwhelmed simply hit the elevator button taking you up. This will give you time to reload. Just keep going up and down until you can get a crawler at the end of each round. This is the best strategy I know of so far, so good luck and leave comments if you have any other suggestions or tips.