Generally these kind of sudden dips happen some twenty minutes before bad news on their official page...
Well, in this case, because of how much people distrust Gox, the only "good news" would be immediate withdraws. The chances of that are slim to none. So anything like, coming soon, limited withdraws, things are going well, ANYTHING except "open for withdrawals immediately" will be considered bad news.
Honestly, Gox may be giving people low 100s or double digit coins soon. Nothing like fear and terror to drive a market.