First thing is to get by the requal. Once you have done that, ask for a meeting with the Senior and discuss your oral and what happened. Ask about the standards of an oral and if the questions asked conform with the syllabus. Mention that you are not looking to bust anyone's chops but that you want to learn from the experience and be better prepared the next time. Tactifully done, you will nail the guy's wad to the wall if the Senior is anything other than a wus just occupying a seat in an windowless office.