1. (Jaume Balagueró and Paco Plaza 2007)
A television crew doing a documentary show called "While You Sleep" follows emergency workers into a dark apartment building. Shortly after entering, the emergency works are a attacked by a resident in the apartment who appears to be infected with something. The building is quickly quarantined, leaving the TV crew and emergency workers locked in with the infected. and it's American remake Quarantine (John Erick Dowdle 2008) take a different route with zombie outbreaks. Unlike most of the other films on the list, the zombies in are contagious. One reason zombies are scary is that they swarm, creasting a claustrophobic feeling that is hard to escape. keeps this feeling of being trapped but instead of the zombies being locked out and trying to get in, they are locked in with the zombies. The zombie count can only be so high because there are only about a dozen people in the building.