Overheard Conversation

The following is an overheard dialogue between a mother and her three to four year old daughter.It was in the dressing room of the JCPenny's where they occupied the room next to mine. The mother was using the dressing room to feed her other infant daughter. I don't know their names so I can't change them. I finished trying clothes on, but couldn't tear myself away from listening so I thought it was worth sharing. What do you do when you hear something like this? I alway feel the urge to say or do something, but I never actually have the courage. It makes me feel like a social action coward.

Daughter: Why aren't there two chairs in here? How come?
Mom: Fine, you want a chair, here. (scuffled movement)
D: But how come this one's different? I don't like this chair. I wish I had that one.
Mom: Just sit in the damn chair, ok? You wanted a chair, I got you a chair.
D: But I didn't want a chair. I don't want to sit down. I just wanted to know how come--
M: Sit down and shut up. Now. I've had it.
D: But I don't want to-
M: (In a very loud voice) SIT DOWN NOW. I'm trying to feed your sister.
D: But I'm hungry. How come I can't have anything to eat?
M: You want something to eat? There are some fruit snacks in the diaper bag.
(Daughter rustles around and gets fruit snacks)
D: But how come there's only one fruit snack. I thought you were bringing three?
M: There were three. You ate one in the truck, one in the food court and now there's one left. That's three.
D: But how come there's not three?
M: There were three. I told you. You ate the other ones.
D: But I thought there were going to be three in here?
M: Just sit down and eat the damn fruit snack.
D: But I don't want to sit down-
M: SIT DOWN and SHUT UP! NOW!
Conversation continues much as above for quite some time and then daughter figures out that she can open the door to the dressing room.
D: I can open this door.
M: Don't open that door.
D: But I can open this door. I just turn here-
M: Shut the damn door and SIT DOWN and SHUT UP.
D: But I can open the door. I know how to open the door. I'm hot in here. Can I open the door?
M: NO.
D: How much longer until I can open the door?
M: Will you please just shut up?
D: What will happen if I open the door?
(The door creaks and then there is a hard slam)
M: You want to know what will happen? You want to know what will happen? They will see me feeding your sister and they will take us away to jail, because you can't do that with the door open. Do you want to go to jail?
D: And then Daddy will have to save us?
M: No, Daddy won't save us. Nobody will save us. We will be in jail. Do you want to be in jail?
D: Why won't Daddy save us?
M: Because Daddy's to busy to save us. He's in California getting trained. Nobody will save us and it will be all your fault that we are in jail. Do you want that to happen?
(Long pause)
D: Mommy? You're upsetting me.
M: Well you've been upsetting me this whole time.
D: Mommy? You're upsetting me saying that Daddy won't save us.
M: Just sit down and be quiet and you better not open that door if you don't want us to go to jail. NOW.
(Daughter sniffles)