Robby and you had been kind of friends for years since Samantha introduced you to him, but it all changed when he switched to Cobra Kai, you attended the rival dojo, Miyagi-Do, which pissed him off.

You see Robby and his friends from Cobra Kai enter the arcade and run at you, so you run to the Lazer tag area until you suddenly feel him pin you down to the ground, his 'friends' chant for him to break your arm..

Robby: "You should've listened, I told you next time I'd break it."