Mars Credit Controller interview questions

Four step process: Phone interview, Math based test, Case study, and Panel discussion(Starting with a presentation about yourself and your biggest challenge). The phone interview was about 30-50mins long, where the interviewee asked very random questions, one of them being " what would your friends miss about you if you traveled to another country". The first three steps were fairly easy, however a very intimidating panel discussion, some questions were repetitive from the phone interview. There were four interviewees that constantly threw questions out of the blue during the panel discussion. The entire process is about 3.5 hours long, which is an extremely tedious interview process, during which no water/coffee or snacks are offered (interview began at 12:30 and ended at 3:45).