139.382.267.410 - 400.000.000 = 138.982.267.410
[138.982.267.410] ÷ [16.923.950] = 8.212.16
So 400mil is literally only a small change of $ 23.64 in this huge market.
It doesn't work that way. The price is determined by supply and demand, which are curves and not single values.
However, I agree that the Mt Gox sales were not a major factor, simply because the sales have stopped and yet the price has started to fall again.
Mt.gox was one of the reasons why bitcoin price is dropping, but you have other reasons too, news about google, fud from China. Its never just one reason, its many of them, always.