This is the tenth level titled "Crash Site" which is based in laos. While going up the river just before you finish up with the boat section a pilot says. .
Welcome to Paradise, In call of the dead you send the crew to paradise, it maybe coincidence but it seems too convenient.
Next bit is from the loading screen, on the top right there is some tropical ferns, this mission is covered in them.
And my last piece of information from http://callofdutyzombies.com/forum/viewtopic.php?f=62&t=11166 is that Aztec Calendar: There is an Aztec calender near the vault with our favorite heroes trapped inside. Here is a picture of ruins in the mission that seem to have aztec or another kind of ancient markings