There are quite a few competent people that play Zombie Mod. Pretty much all the regulars are capable of holding their own. Don't make excuses about not having enough people with skill. You can easily organize a few people to get together. Call out 4 regulars, state the place, and you've got your crack A-Team!
Cheap? How are they cheap. If 5+ zombies get together and bum-rush, they're toast. They require teamwork and effort.
Like I said above, call out the regs, and state the place. Make an effort.
Again, find a good team. Stop making excuses. I don't ever remember camping the room with the heavy vender, or the tubes. I don't make excuses, I find solutions.
You clearly don't, because you have this notion that there are really only two places on each map that are "good": 1) a room with a really heavy object, or 2) the vents/tubes. And as soon as the first place gets destroyed, you immediately panic and rush to the vents.