I went for the walk-in interview which turnout to be a pleasant experience. The interviewer was nice enough and it's more like a discussion. It took another week for the second interview which was meeting up with another two different department leaders. The interviewer is not professional by coming late for the interview and watching on his mobile phone while I am presenting my research findings. Asking a lot of out-of-scope questions. I felt he just want to drag the time to see how far I can go. overall it's very tiring as it took me two and a half hours for the interview.