I do not believe bitcoin falls on the $ 400 price. You are in too much of a hurry to make a conclusion just because the current market is falling and will make bitcoin fall to $ 400. I would rather believe the $ 400 price would not happen on bitcoin.
I think now mining cost of Bitcoin is $5,000. Miners are getting less. Bitcoin does not have any use, it has just become a speculative asset.
I read that shops/stores sell Bitcoin immediately and get cash because of fear of price change. So shops/stores are the biggest sellers of Bitcoin.
Fud is spreading on the entire countries right now and it was too bad for cryptocurrency holders and miners that they cannot get any profit, holding your coins is the only way to survive and wait, patience is what most needed by every traders today.