What should be done after securing weapons in a gun locker during check-in?

Maintaining possession of the key after securing weapons in a gun locker is crucial for ensuring safety and accountability. By keeping the key, the individual responsible can control access to the weapons, which minimizes the risk of unauthorized access and potential misuse. This practice also ensures that there is a clear chain of custody for the weapons, which is vital in maintaining security protocols.

Furthermore, having possession of the key allows for immediate access if there is a need to retrieve the weapons for any reason, such as an emergency situation or when needed for official duties. This is part of a broader strategy to ensure that handling of firearms is conducted safely and responsibly.

The other choices either involve relinquishing control of the key, which could lead to security breaches, or not being able to access the weapons when necessary, which could compromise safety protocols.