This guy could have pulled the greatest heist in the history of mankind.
Steal the cube, take out $500K, leave $1 million inside (fluff it up a bit or put some Styrofoam in the center), then return the cube, saying it was a stunt to draw attention to climate change or similar and you intended to return it. Then they would count the dollars, you'd get a minor sentence (maybe)... Then you get to keep $500k.