Considering that Mtgox hasn't processed any USD withdrawals for over a month and Karpeles is simply lying about that suggests to me that there are serious, serious issues at Mtgox. I wouldn't be surprised if Karpeles takes the money and runs.
How could he take that money?
If he isn't able to send it to users, he won't be able to use it himself.
It's not like he holds actual real banknotes...
(sure he could steal the bitcoins, but then what? change them on another exchange?)