Final answer:
The nurse should ask the caller for details about the bomb while another staff informs security and the charge nurse. This allows for collection of critical information while maintaining a composed demeanor and not alerting the bomber.
Step-by-step explanation:
In the case where a nurse receives a phone call indicating there is a bomb in a client's room, the most appropriate action for the nurse to take is to keep the caller on the line and ask for details about the bomb placement and characteristics while another staff member alerts security and the charge nurse. By doing so, the nurse may be able to gather critical information that can help in the safe resolution of the situation. It is important that the nurse remains calm, does not put the caller on hold, or alert the bomber to the response actions being taken.