What does the “Two-in, Two-out” rule mandate?

The “Two-in, Two-out” rule is a critical safety protocol in firefighting that specifically mandates that two firefighters enter an Immediately Dangerous to Life or Health (IDLH) environment, while two others remain outside to provide assistance or initiate a rescue if necessary. This approach ensures that there are always personnel positioned to respond quickly in case the interior team encounters trouble or becomes incapacitated.

This rule is designed to enhance safety and minimize risks during firefighting operations, recognizing that working within hazardous environments can pose significant dangers. The external team's readiness to act as a backup is essential for maintaining safety standards and effectively managing emergency situations.

The other options do not reflect the intent or structure of the “Two-in, Two-out” rule and therefore do not align with the established safety protocol geared specifically towards operations in IDLH conditions.