UoP was relaxed and not stressful at all. Honestly, don't worry about it 🙂 However, I will say that interview experience will vary from person to person as there is a different interviewer most everyone. Mine only asked me one question and the rest was a conversation. Others had interviewers asking them all sorts of questions -- but the predent said it was still really relaxed, just getting to know them type of questions.
Good luck!