According to the Fifth General Order, when can a sentry leave their post?

The Fifth General Order specifies that a sentry may leave their post only when properly relieved. This instruction emphasizes the importance of maintaining security and vigilance at their assigned location. When a sentry is relieved, it means that another qualified individual has taken over their responsibilities, thereby ensuring that there is no lapse in guarding duties. This principle is crucial in military operations, where maintaining constant watch can be vital for the safety and security of personnel and assets.

While the other options provide scenarios where one might think a sentry could leave their post, they do not adhere to the established regulations. Leaving at one's discretion undermines command authority and the structured environment of military operations. Departing under their own judgment could jeopardize security protocols. Additionally, while emergencies are important considerations, the protocol still requires that a posted individual remain vigilant unless properly relieved. This ensures a systematic approach to duty assignments and reinforces accountability within the ranks.