Here is another award winning theory for you folks.
Blops2 zombies has had a central theme of transportation within it. Green Run gave us a bus, Die Rise gave us elevators, and MotD has given us a plane. Thinking back to Green Run, we know there are train tracks with cars on it, at least one of which that had a power symbol on it. I don't think it's too far of a stretch to see one of the next dlc maps to incorporate a train, bringing this full circle. Also, consider how close Alcatraz and Green Run are proximity wise. Just a short train ride away?
Obviously the players could be teleported, as they were with Die Rise, but just as the prisoners hopped on a plane to escape, they might very well need to bum a ride on a train next. Also, consider the sub-names of the maps. Green Run/ Tranzit. Die Rise/ Great Leap Forward. Escape from Alcatraz Island. All obvious refrences to movement.
There are train tracks that run very nearly from San Fransisco to Hanford, which further supports the possibility of train travel. Oh, and the Chinese were a huge part of the workforce that built railroads. Guess where Die Rise was? That's right. Shanghai.
I entertained the thought of river travel being a possibility, like a riverboat or something, but that was a much greater stretch, as i couldn't find any solid river route from Hanford connecting to other important places.
Since Hanford was a nuclear site, I'm sure much of the nuclear material was transported by train. So, knowing this, could element 115 have been transported to Hanford via train, leading to a "nuclear" disaster?
