Whether it contributed to the crash in the last 24 hrs or it was pure coincidence, who knows. What I do know is I don't believe in coincidence 
It makes sense that they would short BTC, then switch to mBTC, make stupid people panic.
They could either went short on BTC or bought it cheap 2 hours later.
It's very possible that the mBTC switch was a scam attack.
Bitcoinity.com/Markets has a giant "DON'T PANIC" image on their page. Gox, Bitstamp, and BTC-e (the websites you'd need to go through to panic sell your Bitcoin) still price in Bitcoin, so the notion that somebody would not realize something is up is a bit silly.
What website do you believe caused mass chaos?
This week might not be the best time for all of the exchanges to switch to mBTC. Can you imagine having a big crash then waking up to $1 per coin without reading that it had been changed to mBTC? That would be pretty scary for us all!
I think that everyone should just change it on January 1, 2014. The exchanges could start telling everyone that they are doing this when logging in so there is no surprise when it happens. A little expectation setting is a good thing.