Transcript for White Nanny Says Child Is Misbehaving Because 'She's Black'
And you're a brat. What are you doing? Reporter: Before the break, we met many people who passionately stepped in to rescue a child from a cruel nanny. You treat people the way you want to be treated. Reporter: And they do it with a gentle touch. Promise you're going to tell your mom? Every time someone's mean to you? Yeah. Pinky swear. Okay. Reporter: But now we switch things up and change the race of our actors. You're a brat just like your sister. Reporter: Mackenzie is taking care of catori and her baby sister. Color, brat. Reporter: How will people react now? Your mom does not pay me enough to be your nanny. You are such a brat. Sit down! Do you know anything? Go, tori! Pick them up! Learn some manners. Excuse me, can you mind your own business? You can not do this, this is a child. Reporter: This woman instantly confronts the abusive nanny. Are you okay. Sweetheart? I'm fine. Want me to call somebody for you? She's scaring me. Who is this lady? She's my nanny. Where's your mom? Reporter: She's looking for information but the nanny shields herself with a well known phrase. Stranger danger, tori. Stranger danger. It seems you're being more dangerous than I am. You know how these kids are. I'm shaking. I've never seen this. Reporter: And then some career advice. I've had it up to here. I've been watching her all day. Okay? Why you don't find yourself another job? Seems like you're not happy. Find something else to do. You're not very good with children. You should do something else. Reporter: You guys ready? Well, she already does. Our nanny is an actor. I knew. I knew it was you! How are you? Oh, my god. It had to be. Reporter: She was already mean to the child. What about your own safety? I didn't care. I'm bigger than her. You can take her? I can take her. You're so stupid. You're such a brat. Pick it up! Reporter: But like before, plenty of people just walk on by. You're spoiled! I wish you were never born. Pick it up! Reporter: Even when the crayons are flying all over the place, some people stay silent. I froze, like, I had to stop and think about what I would possibly say. I had to say something, I just couldn't get there yet. Reporter: But there are people like Elisa Tejada who do get there quickly. Who you calling? You need to move away from me. Who you calling? That's all I'm asking. Who you calling? I'm in front of subway. She's calling her a brat. Telling her how stupid she is. This is total child abuse. Reporter: And now watch this woman, a student, who calmly watches before slowly heading over. Mind your own business, lady. I'm not gonna mind my own business. Mind your own business. No, absolutely not. I'm not a mother, I don't have kids but I know how to at least treat people with respect. Reporter: But nothing prepared us for this final scene, a band of mothers who start out as complete strangers. I hate being your nanny. I hate it. Reporter: Out of nowhere this woman appears. What are you doing? I'm teaching this little girl manners. No, you're not. Is she yours? No, I'm her nanny. You're out of your mind. Touch her again and I'm gonna knock your teeth out of your mouth. Sit down. Reporter: This woman notices from across the street and then swoops in as a backup. I think we should call the police. You can't be with these kids. She's a brat. I understand. Reporter: And now this third woman joins in and the band of mothers is complete. You can't do this. You could go to jail. You want to go to jail? I'm in charge of this girl right now. No, the police are gonna come. You should not be in charge of that girl the way you treat her. She's grabbing her and screaming at her in the street. You should go to jail. Reporter: They form a circle of protection around the child. You need to come here right away. Reporter: The nanny tries to defend her action and then throws in what turns out to be the final straw. You know how they are. Listen to me. She's black, okay. Are you crazy? So are my children. Are you crazy? I'm married to a black man. She's a human being. Are you crazy? Now you're really done. Now you're done. You should be ashamed of yourself. Reporter: Holy cow. Before it goes any further, time to break this scene. Hi there, I'm John Quinones. This is "What would you do?" Are you okay? You came at her like a tigress. That's my personality. Reporter: And you cursed at her. I almost hit her. Thinking if she did it on the street, what do in private. What were you thinking? I'm the director of the daycare. We have to be very careful who lives in our house, who takes care of our kids what place we take them. Because it's very dangerous these days. Reporter: Supermoms to the rescue. Don't mess with them.
This transcript has been automatically generated and may not be 100% accurate.