What is required of the sentry under the fifth order?

The fifth order of a sentry is to "Quit my post only when properly relieved." This command emphasizes the importance of maintaining security and order at a designated post. A sentry's primary responsibility is to ensure that the area they are guarding remains secure. Leaving the post without proper relief could create a security lapse, potentially endangering personnel and the facility.

By adhering to this order, sentries help uphold the chain of responsibility and ensure that their duties are fulfilled without interruption. It establishes a clear chain of command and reinforces the need for proper communication and protocol in military operations, which are essential to maintaining an effective security posture.

In contrast, the other options, while they may reflect important duties or responsibilities, do not specifically pertain to the fifth order and therefore do not capture the core requirement placed on a sentry in this context.