I think permission is not that hard. I forgot the review process. Yeah, reviews can take a long time. But this is fictional drama anyway, so yeah, they kinda skip that process.
But since the beginning of this drama I have this one question that keep nagging in my mind. If the Saeki method is kinda like the top notch mitral surgery method and the paper got a high impact factor, how come only Saeki that can perform that procedure? From my understanding, impact factor is earned not just because of the novelty of a study, but how much it cited on other scientific articles, implying reproducibility of the study/method. In fact, all the papers that were shown in this drama are probably case reports. Which has a somewhat low evidence value, compared to a randomized controlled trials, or systematic review. That's the plot hole imho.
Still, I enjoy this medical drama so much.