MMMHS Hi There! I don't know how it would work but I have had a friend go through PD at Nossal so I can't imagine it would be too different. The questions would probably be asking about your interests, extracurriculars, reasons why you want to go MHS etc. I would answer the question in a way that allows you to make connections to MHS. What I mean is you shouldn't answer the questions for the sake of getting in ONLY but also being able to connect with the interviewer (Which I would assume is Dr Mordini but I could be wrong). I would also do a bit of research into what MHS provides and what you love about it. MHS has a ton of clubs and by talking about them, it shows you've done your research. Maybe be prepared to talk about your favourite subject!
I haven't done PD for MHS but I hope you get in! Good Luck!