Duffy is a good friend of the bully. Despite this friendship, he does not stay as a neutral bystander. He has the courage to stand up for the bullied girl and tell the bully that he doesn't like her behaviour. He is not just going to be a bystander.
The three actors played the roles skillfully. The bullying felt real. The bullying felt horrible. The whole audience felt really bad for the bullied victim. They really empathised with her.
I hope we can all learn from this example. It is not okay to just stand back and allow bullying to happen and not try to do something about it.

