Some one want to buy bitcoin at a low price I guess.
nah, this actually will drive up the price as people will trade IRL with an extremely limited supply
If history is any indication, a hack generally does not drive the price up. I realise it might seem hard to believe at this point, but not everything drives the price up. Sure, nearly everything does, but there are exceptions
I doubt it's a coordinated attack. So far there has been one (1!) confirmed case, as BitcoinCentral + Instawallet + Paytunia is the same company.