Fill in the blank using the appropriate conjugation of the given verb (vouloir):
Hier, tous les gens ______(vouloir) parler ensemble.
I think the verb should be conjugated in the Passé Compose tense, as the action was momentary, associated with a particular instant of time, and not continuous. However, the text seems to use Imparfait to arrive at the answer.
Could someone explain which tense is more appropriate/correct in this case? Also, is there any definite rule which can help distinguish between cases where one of the two tenses have to be used?