Controlled Demolition ?
If a few whales each had around 1000+BTC on GOX and 1000 on other exchanges...
If they were convinced that their 1k on gox was lost Then wouldnt it be prudent to get together, Dump massively on both platforms until they had nothing left on Gox but fiat,,
FUD would do the rest in dropping the market way down.  They could then use the fiat on a safe exchange to buy up their lost gox coins cheap whilst still having fiat in gox which could possibly be recovered?

ie. They crash the market in order to buy up the same amount of coin in another exchange and still have fiat in gox.

If so, sub $400 is possible imho.

(BTC grew so quickly in value recently that it essentially became premined. )