Continuity mistake: Before the Turtles were carted off to the arena in the previous episode, they were disarmed. But once they have been confined to the gladiators' quarters, when Ralph asks about Traximus ("Who's Mister Sunshine?"), at that very moment he has his sai back in his belt.
Continuity mistake: When the Turtles and the rest of the gladiators are to be ferried up to the arena, Gruel the overseer refuses to give back the Turtles' weapons. But once the Turtles are on the elevator platform, Raphael and Donatello have their weapons stuck in their belts; then the scene switches, and the weapons are gone again just before Traximus unpacks them for the Turtles to take.