Sahas Subramanian discussed design patterns for scalable test automation using Selenium and WebdriverIO. He addressed various questions from the audience, including handling security authentication pop-ups, SOAP/SOAPUI testing, creating wrappers, and implementing TDM. Sahas emphasized the importance of page reloads, asynchronous behavior, and avoiding thread.sleep() in tests. He also discussed the benefits of using Sauce Labs for test automation, integrating WebdriverIO with CI servers like Jenkins, and leveraging UI map repositories. The key takeaway is that scalable test automation requires a combination of practical patterns, frameworks, and tools to achieve stability and maintainability. Sahas encouraged evaluating different choices based on goals and development stacks.