Which of the following is a "red flag" sign indicating urgent evacuation for a casualty with TBI?

The presence of a witnessed loss of consciousness serves as a significant indicator that a casualty may have sustained a more severe traumatic brain injury (TBI). This symptom elevates the urgency for medical evaluation and evacuation because it suggests a potential disruption in brain function that can lead to further complications, including intracranial bleeding or swelling.

Witnessed loss of consciousness can often signify that the brain has been seriously affected, and timely medical intervention is crucial to mitigate any possible long-term damage. In trauma scenarios, prompt assessment and treatment are essential in managing TBIs, and the presence of this symptom usually prompts immediate action.

In contrast, stable vital signs might indicate that the casualty is currently stable but do not provide enough information about the potential severity of the TBI. Minor confusion or a headache without other symptoms may not necessarily indicate an urgent need for evacuation. These conditions can vary widely in severity and may not reflect immediate, critical danger, particularly in the absence of more alarming symptoms such as loss of consciousness. Therefore, the witnessed loss of consciousness is the key symptom that marks the need for urgent action.