Final answer:
The most immediate threat to safety should be addressed first, which means responding to the duress alarm, followed by searching for the missing patient under the Mental Health Act, and then escorting another patient to x-ray.
Step-by-step explanation:
In a healthcare setting, the priority should always be to address the most immediate threat to safety. Therefore, the correct order of actions would be option B: Respond to the duress alarm, search for the missing patient, and then escort the patient to x-ray. The duress alarm suggests an immediate threat or emergency on the ward, which could potentially affect multiple people, including patients and staff. Once that is under control, the next priority is to find the missing patient who is under the Mental Health Act, as they might be at risk or pose a risk to themselves or others. Finally, after the more urgent safety concerns have been addressed, the patient can be escorted to get an x-ray, provided there is no immediate medical necessity that would prioritize it over the other situations.