Retirement shall occur in accordance with the State Personnel and Pensions Article. Except for the Secretary, retirement is mandatory as provided in § 24-401(c) of the State Personnel and Pensions Article. The Secretary may apply for disability retirement on behalf of a police employee in accordance with § 29-103 of the State Personnel and Pensions Article. This subsection does not prevent a police employee from exercising the individual’s rights under § 21-111 of the State Personnel and Pensions Article. Notwithstanding any other provision of law, a police employee, on retirement in good standing, may keep or acquire the handgun issued by the State to that police employee if: the police employee reimburses the Department for the replacement value of the handgun; and the Secretary authorizes the transaction. The Secretary shall adopt regulations necessary to carry out this subsection.