Penn took the punch in the face. Brilliant! The idiot hit him first! This wasn't Penns first rodeo, he knew how the school punished fights and he knew first hand that the first to hut got a lot more trouble . He even had witnesses! Kara might not back him up but Avalon totally would!
'"Oh you're done!" Penn pounced at Justin, no real plan apart from punch and kick until someone pulled them apart. He usually tried to rip some feathers out of his opponents wings, nothing says 'I got my ass beat' that missing chucks of feathers, they take ages to grow back too so the loser walks around with that reminder for weeks. Pen was determined rip out as many of Justin's as he could.