Mark was on IRC (the last time this happened) and said that the loop was activated by his "security system" that goes off when someone places and huge market sell order. The reason for his weird "security system" is to prevent a repeat of what happened several years ago when someone hacked the site and faked a market sell all the way down to zero!
I can't see how this would help that situation.
If it were me making a huge sell just now I'd be pretty peeved that the whole world has now been alerted to the fact.