Since Gox takes fees on both sides, 5 millions USD of fees are in btc, it doesn't really help them in their cash flow issues.
I've read somewhere Gox owns thousands of bitcoins through fees and re-investments, they cant sell their coins on their platform and hold worthless Gox USD. can they?
The default for new accounts is to take all fees from the fiat side, and has been so for a year or so. Many old cusumers (e.g. me) have switched on this option as well. Which means most of their profit from this year will be in fiat. The 2.5% currency conversion fee for mixed currency trades are in fiat as well. MtGox can not sell BTC on their own platform. I don't know if they are allowed to trade BTC on other exchanges. Their strategy so far has been to use BTC as BTC, e.g. when buying other companies (two so far).