Translation:My friend is injured, please call the police for me!
Why are the police being called for and not an ambulance?
Maybe friend was assaulted.
On the other hand, does 报警 just refer to calling police, or could that be for calling any emergency response, like calling 911 in America?
'Hurt' is accepted as a synonym to 'injured' in all the rest of the sentences in this exercise, for what I noticed...