For now price tanks 400, watch the price closely as I still believe there is a link between cost of production and actual price .

If its not profitable for a miner to mine then he will buy BTC so miner that shut down , become buy pressure, so price even if it goes below the average cost for production eventually it will get back on the resistance thats formed around the average cost for production.

Regarding miners that shut down when bitcoin becomes cheap, The only time I saw difficulty drop was when it met the average cost for production back when it struck 200.

And the difficulty dropped very little before stagnating for a period.(as price did)

Of Course the price has plenty of room to the upside , but for the downside part I personally dont see any space left.