Those "bitcoins" from Gox are never getting out.
They don't have to get out.
Mark can easily just sell them.
Either way. Shorting bitcoin NOW is the way to go.
If Mt.Gox will completly default -> price will drop hard
If Mt.Gox will allow withdrawal of bitocoins -> price will drop hard
Either way, we will go down to 100-250$ per bitcoin and stay there till mass adoption really kicks in (2-5 years).