Whales are buying BTC in large quantities to move out of Gox. They don't necessarily need to cash out immediately. They could be holding BTC for speculative purposes as there is no other exchange that could possibly handle that volume (neither can Gox, that's why the price has moved so dramatically).
This is quite obvious when you see such large buy orders in 1 minute time spans vs a gradual move up in price.
They are buying BTC in large quantities to move out of MtGox, but they don't move it out of MtGox? Is this some kind of New Speak for speculative buying because they believe the price is going up? Not Exactly New in the world of Bitcoin trading. What about the even larger price increase at Bitstamp? Is that people buying BTC on Bitstamp to move out of Bitstamp, but they don't actually move it out of Bitstamp, or something? No, this is entirely in your own head.