So I made a video tutorial to help players who wants to fill their banks up real fast.
The only maps where this works is Tranzit, Buried, and Die Rise.
The recommendation map is Buried.
Also, I know that this isn't modding and I apologize, but there isn't a tutorial section of Zombies. So I'll leave this here unless if a mod doesn't want this here, then it's entirely up to them.