What federal law says that leaving Mission Control during a crisis is a felony? What law says that you must do what your boss tells you? Law enforcement officers have to enforce laws. They don't just get to decide that people should act in a particular way.
I don't suppose "leaving mission control" in contravention of an order to stay during a crisis is, in and of itself, a felony.
What you're likely to find is an issue is that the security guards at NASA can arrest, if the links above are correct, and you're likely to fund yourself in a predicament if you try to leave and they don't want you to.
I'd imagine working at NASA, and at least some other space launch companies, especially those that provided services to government and defence agencies, come with additional conditions beyond what one might expect stacking shelves at a supermarket.
