Although the game Evan references in the conversation is the mega-popular Fortnite Battle Royale, he's actually playing Horizon: New Dawn. Also, he can completely pause the game he's playing, meaning the game isn't multiplayer and he isn't playing with anyone. Of course, it is possible that he's simply in an online conversation, not playing with anyone, and talking about a previous match.
In class, Sam is wearing his noise-canceling headphones and can't hear his teacher. When Sam is in the closet, he is wearing the same headphones and looking down, yet he looks up right when the other girl says 'hey,' like he heard her. However, noise-canceling headphones don't cancel all sound and he was only pretending not to hear his teacher to avoid having to face reality.