Interview process extended several days and was conducted through multiple interviews. They definitely want to vet you to make sure you are prepared and can handle an advanced summer internship/job. The stress and pressures are real so they want to know your true self during the interview process.
Thank you for sharing your experience. We definitely do our due diligence to vet people, as we want to ensure we're selecting the right people for the role. It's certainly not for everyone -- but it's magic when it's the right fit.