The Commissioner of Mental Health and Substance Abuse Services is authorized to establish training schools within the Department or within any of the institutions operated by the Department, for the training of necessary personnel for the institutions, or may arrange for the training of employees or prospective employees in any public or private school or institution within this state or elsewhere having available facilities for that purpose. Funds of the Department and/or institutions under its control may be used to pay salaries to employees, or to pay tuition and subsistence for employees or prospective employees, while receiving such training. Any employee or prospective employee who is paid a salary, or for whom tuition and subsistence are furnished, while receiving such training, shall be required to enter into a contract prior to receiving such training, that unless he continues in the employ of the Department for at least a period equivalent to the training, he will reimburse to the Department the sum paid to or for him by the Department during the period of his training.