I don't believe Silk Road is going to crash.
By 'The Great Silk Road Crash' I was referring to the BTC price crash that Silk Road disappearing would precipitate.
I don't believe SR is large enough to crash Bitcoin. I don't think we'll even see that big of a dip in prices.
Silk Road revenue is said to be "approximately USD 1.9 million per month". If this demand suddenly disappeared then I think there would be a massive dip. You can also add market panic to the mix.
I want to add that I am not trying to spread FUD with this topic - I just think this is something Bitcoin will have to go through during its evolution.