Those employees have done us a disservice not blowing the whistle on this long ago. I would have liked to know that deposits were being used to buy 3d printers, robots and cars.
The employees had no one to report it to. It wasn't clear that Mt. Gox had a legal obligation to segregate customer funds. The Japan Financial Services Agency wasn't regulating Mt. Gox.
Now, at a real brokerage, in the US or Japan, dipping into customer funds is a crime, and employees have an obligation to report it.
Once there's a bankruptcy and fraud is suspected, it's all different. Now it's time for employees to cooperate with the cops, so they don't take the fall for the crime. (In the US, the first person to report a multi-person fraud to prosecutors gets off. But
only the first person. Sometimes this results in a race to the prosecutor's office.)