and reading your and others comments makes me really sad, because it shows how much we simply do not understand children. Stop treating them like mini adults.
I was a strict parent, and tough on bad behaviour.. But I also understood the difference between a temper tantrum, where the child is misbehaving, and an emotional melt down, where something has triggered a distress response. And the trigger can be something 'insignificant' and is often not the real issue.
A child in emotional melt down is physically incapable of stopping by choice. Their brain is being flooded by hormones and they need help from someone else to regulate what is going on. That will vary child to child, some need space, some need to be held/hugged, some need you to just be with them while they calm down.
For those saying that adults have to control their emotions and they need to learn, you'd get arrested for that behaviour as an adult etc etc, yet again, it is simply not understanding the physical difference between the brain of a child and the brain of an adult.
An adult's brain has a fully formed frontal cortext. The decision making part of their brain is able to override the parts of the brain reacting emotionally to an event. Their fully formed brain can make a choice to hold on to the emotion and not express it. A child cannot do that, a child's brain is not fully formed, and when the emotion hits the brain is overwhelemed and the emotion takes over.
As parents we need to help the child to calm down, and get back to a place of regulation and then we can talk to them about what happened. (eg you hit your sister, so now the consequence is) and help them to begin to see what they can do when they feel that way (when you are angry you can hit a pillow) but it is an 18 year long process, and we need to have age appropriate expectations.
'Punishments' rarely work. Consequences do.
But building positive things into your relationship is also essential, so if this is the only time you can take them out 1:1, then don't give it up. You and your child need that too.