This was fake.
However if real, you're supposed to get on a knee and meet them at eye level, because you don't want them to think you are an adult and they are a child. God forbid
Then you ask them about their feelings and what made them do it.
Then you explain to them that what they did was wrong, but that it's okay to feel how they felt because feelings are how you feel.
Then you try to relate to them and explain how you have feelings sometimes too. Because if a child can relate to you, then they will see you as "cool". And every parents dream is to have their kids thinking they are friends.
Lastly, you hug them and give them their tablet so they can go back to not having much human interaction, but at least be quiet for a few hours.