The manual door release couldn't be further from "secret". It's so obvious that almost every first-time passenger thinks it's how you're always supposed to open the door.
1. The woman in this story wasn't in the back seat.
2. The whole concept of the "child safety lock" feature in cars is that we want to make it difficult/impossible to open the back door from the inside.
but... weird friends are a blessing. at least in my opinion. cherish them. they'll help us all see things in a new light.