What should the third arriving Engine Company prioritize?

The third arriving Engine Company should prioritize acting as the Rapid Intervention Crew. This is crucial because the Rapid Intervention Crew (RIC) is specifically designated to provide immediate rescue for firefighters who may become trapped or endangered while performing their duties. Having a dedicated team ready to respond to emergencies within the emergency scene significantly enhances the overall safety for all personnel involved.

As the incident evolves and more resources arrive, the previous units may be engaged in critical functions, such as establishing command or managing ventilation and utilities. The RIC's primary focus is to be on standby, prepared to intervene at a moment’s notice, ensuring that the incident remains safe for all operating personnel.

While the other options involve important tasks, they are often managed by preceding arriving units. Therefore, positioning a crew specifically for rapid intervention is vital to maintaining a safety net for firefighters on the front lines of firefighting operations.