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 .
Someone that's been involved in BTC and just don't see a future for it anymore or they are relying on the funds they have stashed away in BTC.
Early adopters might get sick of holding onto their hats since $5/BTC and feel like $1000/BTC might be a good exit point because CPU mining wasn't that hard.
Late adopters might get sick of holding BTC because they bought in at $1000/BTC and they're sick to their stomachs at 80% loss.