Two theories:
1. Back then they dont necessarilly have all these so called (extra's) in a movie, so this lady could have
been a schizophrenic who accidentally got in the footage... (szchizophrenia- 'distorted reality, hallucination, delusional)
2. Or the lady is an 'Extra' that was suppose to play a (crazy) woman, (since, I don't think schizophrenia was ever diagnosed
at those times) talking on an object <------ hence the 'crazy' part...
Mystery Solved : )