Alright so I searched all over the Internet to see if anybody had found this, and I found nothing. So i guess i discovered this Easter egg!
In the mission "Time and Space" There are multiple refrences to the show "Breaking Bad". When you go down into the Cocaine Shelters, there is a room in the back that contains all the refrences. These include an axe in a barrel (from when Walt was destroying the evidence), A security camera (A refrence to Gus planting one to watch Walt), The pack of cigarettes with the Ricin cigarette out, and of course the biggest one a bright green box cutter in a pool of blood, representing when Gus killed that guy with the box cutter. To find the box cutter and the cigarette, jump on top and look behind the boxes.
ALright guys! hope you check it out. Pretty cool discovery. the room should light up when you walk in.
It's Zombie's subforum. Personally, I don't care neither about campaign or multiplayer. I suppose it is a nice find, but what are you expecting as feedback? Best think you can do is make some screenshots and add this info to Call of Duty's wikia. Also, mission is called "Time and Fate".