User blog comment:Argorrath/Treyarch posts a message of zombies; possibly hinting to a DLC 4/@comment-66.87.118.7-20130804052616/@comment-67.87.55.100-20130804054103

They're dead, in Mined Games you go to Round Infinity, which is thoretically the end of Buried, where the New Crew are dead. So, however long it may have taken them, they were still overrun by zombies and killed.