Colin first walking tends to evoke this, whatever version you're watching.
In the 1993 film, Archibald Craven finally calls out Mrs. Medlock on her zealously overprotective behavior.
"She's just a child. I left you in charge."
Much earlier there's also Colin standing up for Martha. The servant girl is blamed for Mary finding Colin and Medlock starts to slap her and tell her she'll be sent away. Colin threatens to send her away and shuts down the beating at once. Medlock is completely shocked that he's giving her an order.
Mary calling Colin out on his tantrums — as the author points out, your typical little girl of the period would've been frightened and run away, but Mary isn't at all typical, so she just gets mad. She's every bit as willful and spoiled as Colin, and it never even occurs to her to indulge his tantrum. Colin's been so used to everyone giving in when he screams 'because he's sick' that when Mary not only refuses to do so, but informs him just as loudly that he should stop being silly as there's nothing wrong with him, he's so impressed (and startled) he believes her on the spot.