When calling to report an emergency situation, you should stay on the line to give information to the attendant unless:

there is immediate danger in the area

Explanation: Calling to report an emergency situation could be very helpful in other to salvage an impending disaster or help manage a situation. However, some necessary or vital informations may be required of caller by the attendant in other to assist the emergency service personnel know what the current situation is and how to prepare and manage such problem.

Conversely, when there is immediate danger in the reporting area or at the moment of making the call which could put the life of the caller of that of other people at risk, the caller can end the call. A situation where workers or passengers are being kept hostage by terrorists or kidnappers who aren't permitted to make calls.

i'll just take the points xd