1. Purposely raise the price of BTC, attract traders come to Mt.gox and deposit BTC. Market situation: Sell >> buy;
2. Block cash withdrawing, most of traders found it's not easy to get out money even they can sell BTC with higher price.;
3. Some of traders will buy back BTC, sell == buy, price was going stable and higher than other exchange markets;
4. Mt.gox sold customer's 40,000 BTC, and block withdrawing BTC;
5. The price of BTC dropped accordingly
6. Mt.gox to open cash withdrawing and continue to block BTC withdrawing, traders will trend to sell BTC by lower price and get cash back;
7. Mt.gox will buy back 40,000 BTC to balance account

It's not surprised to see announcement tomorrow: BTC withdrawing will continue stopped but cash withdrawing will be quickly and smoothly