You have to balance that with the fact that the doctor has the right to stay employed. If contents of the doctor's brain (including the medical history of his p

You have to balance that with the fact that the doctor has the right to stay employed. If contents of the doctor's brain (including the medical history of his patients) are so critical that the practice would lose customers if the doctor left, then instead of pursuing legal action against the doctor if he leaves, the practice should ensure he is compensated enough that he has little incentive to leave.