In your opinion what are the reasons that let someone start dumping his bitcoins and walk away ?
I personally (and this is just my opinion) that it's more panic then simply his need of money or something else , as we saw on the BitcoinXT last time , people started to panic and simply sold their bitcoins and that caused a drop in the price .
Moreover, they began to fear losing their money, and at first they lost confidence in bitcoin that's why they sell panic just like that. Sell panic is so contributing to the drastic price reduction, they should not need to panic just because of FUD, manipulation etc.