Im stuck, and ive been at this part 4 times now with 3 and 4 people. Are there any good ways to fill those pumps up quick? We make it there as early as 12 and it just seems like we run out of ammo or someone gets downed. The people I play with are pretty good at zombies in general. We can make it to 25-30s pretty easily. It just seems that holding up behind the pyramid is a bad idea. We use claymores and have are ray guns. It just seems that the second one of us goes down all hell brakes loose!