I don't know - I have a hard time believing that this is a reaction to the MtGox news. I'm more inclined to believe that there is some insider information that we'll all learn about days/weeks/months later..
It's probably a whale trying to manipulate the market into panicking using a small dump after the gox coins news. Whales often wait for some big news, then try to move the market with a big sell or buy.