Experiencing an emergency in a spiritual sense is having to deal with the unexpected, which may test our perceived limitations.
Psychological / emotional perspective: Any emergency puts our emotions under stress and so it is in dreams.
If we are under stress in waking life we may dream of an emergency and equally if there is an emergency in real life we may dream of explosions and other such images.
Material aspects: What seems like an emergency to one person may not be so to another. Anxiety dreams often contain some element of the necessity for immediate action.
Dreams of an emergency signify that you are releasing stress, anxiety, hurry, and worry. This dream may be flagging you down to pay attention to aspects of you that have been ignored for too long, and now they are in urgent need to be paid attention to. This dream is a wake up call.
If you are dialing 911, then you are calling out for help. You are in a situation that leaves you feeling helpless and you need support to return to balance. See Hospital.