Well, that happened for the first day we originally heard USD transfers were stopped.
Can you say for definite that this was caused by the stopping of USD transfers? If so, what did people do once they sold their BTC?
They now have USD they can't do anything with.
People BOUGHT on day one. Some people paid a premium to get out and sell on Bitstamp [hence the quick fall to 90]
Those who had their asks enjoyed a nice premium price for the risk they are taking in holding.
Maybe people will really panic now and get out BTC.
Or maybe they say, "Shit, this is going to hell - I'm selling before we drop more"
No matter what Gox said, it was bad news
So if USD isn't resumed and they sell, they still can't mitigate that risk. The only thing they can do is transfer out and sell at a different exchange which does allow USD transfer.
I can't see anyone thinking "I'm going to sell my Bitcoin for a currency I can't receive." rather than "I'm going to take my bitcoin to sell elsewhere and I better do it quick before the price falls further".
A great deal of the bitcoin price is based on psychology. I say, "This news is going to make people panic. I think others might sell and put the price down. I should beat them to it."
Then the others who went, "Crap, I didnt really think it was that big of a deal - I'm out too"
So, bad news -> beating people to selling. Even if you cant cash out, most people are confident it will be back online sometime in the future.