In a decision that some on Wall Street see as a sign that Wall Street’s involuntary “RIF” (reduction in force) may soon become a more widespread and voluntary flight as its most experienced and talented bankers head for more appealing pockets of the financial system, Zoe Cruz plans to build her own hedge fund rather than rejoining the investment-banking universe.

That news may come as a relief to anyone who feared becoming Cruz’s subordinates on Wall Street. The hard-driving former heir apparent to Morgan Stanley CEO John Mack is known for her forceful and demanding style. “There is no ‘softer side’ to Cruz,” says one former Morgan Stanley banker.

That didn’t stop other investment banks, from boutiques to bulge-brackets, from wooing her, just as they did the other high-profile female casualty of the market meltdown, former Citigroup highflier Sallie Krawcheck. But while Krawcheck chose to return to the heart of Wall Street as head of the global wealth management business for Bank of America, Cruz has opted instead to move to the part of Wall Street where she’ll be judged only by her results, not her personality. Cruz, 54, is launching a $200 million hedge fund called Voras Capital Management, which will reportedly focus on distressed debt and macro calls on currencies and securities.

That’s a great move for Cruz, whose years of experience watching markets has left her with great instincts for both risk and opportunity. In 2007, Morgan Stanley managed to beat Goldman Sachs at its own game by shorting subprime securities. Cruz was also in touch with enough of the right people—and listening to them intently enough, even when they challenged conventional wisdom—to realize that the subprime problems would filter through into even high-quality mortgages. She began warning clients early in the summer of 2007, earning the lasting gratitude of several of them. Cruz’s problems managing her own staff, however, meant that Morgan Stanley itself stayed at the party too long. Depending on whose version of the story that later made its way around Wall Street you believe, either Cruz never explicitly told her subordinates to walk away from a big bet on a complex strategy that included a bullish stance on triple-A (non-subprime) mortgage securities, or else those subordinates, resenting her style and her rapid rise to power, decided to defy her. Whatever the case, the bank ended up stuck with a $3.7 billion loss, for which Cruz ultimately paid the price.

Cruz’s background as a foreign exchange trader and her expertise in the derivatives markets is likely to make her a great hedge fund manager—word is that investors are eagerly scanning the preliminary marketing material on offer and waiting for a complete offering document to emerge. But the hedge fund world’s gain may be Wall Street’s loss.

Indeed, Wall Street may be losing not only those who bear a degree of culpability for the mess that we’re in—the bankers who ran the CDO-creation machines, paying less and less attention to risk and overriding or firing anyone who dared to challenge them. Lehman’s Dick Fuld will never work on Wall Street again, and that’s a good thing—he encouraged risk taking and fired people—like Mike Gelband, who saw early warning signs of the problems in real estate—for being too pessimistic. But there are others—from mid-career bankers with great track records, to former senior executives with unique skill sets like Zoe Cruz—whose expertise could have been invaluable to Wall Street institutions as they struggle to reinvent themselves in the wake of the crisis.

“The problem in all periods like this is that you don’t lose only the people you want to lose, but also people that you may need,” says Wall Street recruitment and compensation expert Alan Johnson. “They are the people who have the most options right now, and they are in demand. The business of Wall Street is complex, and, now more than ever, financial institutions need people with the skills to navigate that complexity.”

But one former senior investment banker dealing with his “legacy” issues points out that a new kind of “career risk” is taking shape on Wall Street. Anyone whose responsibilities including overseeing the securitization business or whose subordinates racked up losses will find that that follows them for the rest of their professional lives. “It doesn’t matter what else they have done; that is what they will have to explain away anytime they talk to someone about a job. No one at a top-executive or board level could afford to deal with the career risk of hiring Zoe to run their bank or even a fixed-income desk because of that loss.”