I agree. It also makes me wonder whether this is a possible attack vector against the market at this stage. A relatively small sum of money can be used to introduce significant instability into the market. Probably not very efficient though, I guess over time speculators would catch on and start to anticipate the up- and downspikes. Also it remains to be seen what the rates settle at after the last drop. I'm actually a little surprised that the effective drop was only 10% or so.
Currently, there's a little under 2000 BTC being sold at or below 1USD/btc.