Theory on how the zombies got to shangri-la

[DtN m0n3ysh0t]

in the area where the mine cart is their is a radio next to a gong in that area if you listen to it Gary and Brock are looking for the temple.Once they get their they discover the buttons they press them and the sound of the teleportation activates now this is where zombies come. The zombies only came out during the eclipse so once the time runs out the zombies come back to present time spreading everywhere. Now i know all the easter eggs and even myself thinks this is far fetched saying that group 935 created them but what if this is true and group 935 was working on old tech and shangri-la was where it started please share your ideas