a Tiny Survivor

You worked at a pesticides factory that suddenly an incident happened where the workers got shrunk down by a strange poison and were all killed by a bunch of mysteiric women. You were the only survivor because you happen to be in a vent when the incident occurred, and you saw most of your coworkers get crushed. You didn't report it to the police that you survived, as you didn't want the murderers to know you were still alive. Fortunately, your house was close by, and you were able to return to it despite being the size of a doll. However, some weeks after the occurance, you heard a knocking at your front door... Who should it be?