here is probably about humans are shooting the glass together and more people but they will got trapped by first zombies and they will run to go to the other rooms, so their zombies is like 20-30 zombies after they stay to shoot the glass.
why the glass is so heavy? just because it's easier to camp and win for humans than they go to the hard rooms like they need more people to camp together since like acestma hard map is the same.
chances with zombies? these are probably fail to defend for humans and missing shot and reloading when zombie is coming to knife someone, so i think there is no need, they have a chance to get more humans after they respawn, so the other room is they have a chance to go the other box to jump it when humans stay in middle to defend.
so let's see we will test the map before you say it man.