It's not that it should, but that it can.

I'd say $3K is improbable, but $6K would be completely typical for BTC. Just another day in the market. The historical charts are riddled with drops like that, and surely there isn't a fundamental explanation for every one. Sometimes the market just drops. Supply and demand, etc. BTC is a very thin market. It doesn't take that many coins to spark a selloff, especially if the underlying market conditions are bearish.