As my comment says, if you were to buy any BTC on Mt. Gox, you have no way of transferring it elsewhere or spending it. All outbound transfers are turned off, and people have no way of knowing if or when transfers will resume.
There's a belief that Mt. Gox is insolvent or will be shortly. Whether that is true remains to be seen.
But if Mt. Gox does indeed go bankrupt, there'sthere is a school of thought that says you are better holding fiat currency in Mt. Gox than holding Bitcoin. There is an established body of law in Japan and elsewhere abouutabout companies that go bankrupt while holding customer funds. There is very little precedent about what to do when a company goes bankrupt holding customer accounts in Bitcoin.
Since you can'tcannot get either out of Mt. Gox at this time, people are hesitant about holding BTC. That's just one of the factors contributing to the current pricing.