

**10,000 zombies is for one of the avatar shirt unlocks. There was also a horde that had a clown in the lead honking away that I believe could count to the ignite a clown with molotov if you bring one with you. You could also camp here with a melee weapon and work on your decapitation with melee achievement and chainsaw achievement if you had enough gas. It took about 400 kills before the director even bothered trying to send in a special infected.and they're usually so far away you mow them down with the horde before they get close. If things get too bad you can just back into the safe room and the AI will cover the door while you recoup or heal up.
L4D2 SAFEROOM DOOR FULL
You will get 15 second breaks or so after you've slaughtered a horde and be able to run into the safe room grab full ammo and maybe heal if you need to. On easy solo campaign I can net around 1,000 killed in 30 minutes. They get funneled down 2 hallways but you can just cover the one and kill most of them. If you just sit 1/2 in the door and 1/2 out the door and look down the long hallway toward where you came from you can just wait for horde after horde after horde of zombie rushes.

Inside the safe room there is M16/Sniper/Shotgun + ammo + 4 health packs.
Location: BEFORE you actually close the door on the section in Dark Carnival where you can get the mustachio achievements (after you've opened the gate and made a mad dash for the safe room) So now Ill share it to you.What this plugin does at round start, it locks all end saferooms and when all players gather and one of them tries to open it, a countdown timer will activate (lets say 60 seconds), spawning 3 mobs and keep the door lock until it ends.
Update: Safe Room at end of Dark Carnival - 4 before you go into the stadium for final stand.
