The Left Hand of the Magician - S1-E5
Plot hole: Luca draws the sketches of a magic trick, but they contain a fatal flaw that would kill whoever is doing it. He is hospitalized so he takes no part in the setup, so there is basically no chance that the flaw would go undetected. Other people are building the stage and device and they'd do at least a couple of tests before debuting a death defying stunt with live arrows and fire during the show.
The Left Hand of the Magician - S1-E5
Plot hole: Luca is the one who set a deadly trap, but somehow doing that he realises that it was his rival that killed his dad, and accuses him of trying to hurt Fujiko...which he did himself! In fact, this begs the question; if the ringmaster wanted to be the one and only to have access to his father's tricks, why was Fujiko the one doing the magical act? It would have brought fame to her and kept him in the shadows. If he knew that the act was flawed (and it was not, since it works), another death on stage would have tanked the show forever, so obviously it was not what he was after either.
