Final answer:
In a vehicle extrication scenario, the 50-year-old female in cardiac arrest would be considered the lowest priority for rescue efforts due to the low survival rate in such cases, based on triage protocols.
Step-by-step explanation:
At the scene of a vehicle extrication, priority is given to patients based on the severity of their injuries and their potential for survival. In the scenario provided, the least priority patient would be the 50-year-old female in cardiac arrest. This is based on triage protocols that aim to do the greatest good for the greatest number of people. Given that patients in cardiac arrest have a low survival rate, especially in trauma cases, emergency resources may be better used on patients with a higher chance of survival. Therefore, the 50-year-old female in cardiac arrest would be considered the lowest priority compared to the others who need extrication but are still alive.