Hey all-MS1 at SKMC here. Jefferson has 2 interviews-1 student (completely closed file, all they know is your name) for a half hour and one faculty (open file-they will ask you about your app). The faculty all were chosen because they're very nice, kind, sane people and so no matter who you get they're extremely sweet. Jefferson doesn't do pressure interviews, they genuinely want to get to know you and put a face to a name. If I recall correctly, my interviewer and I talked activities I did in undergrad, what I was doing during my gap year, etc.
Also, the admissions deans do a great job of thoroughly going through every single app by hand, so by getting an interview they're already fairly sure that you'll fit in-the day is more of just "do they seem like they're app makes them out to be" and "are they normal/can hold a conversation/a nice, genuine person"
Also, for those wondering about cookie hour, it is by no means mandatory but I would recommend it, even if your there for 5 minutes. Just make sure you go up to Dr. Brooks and Dr. Callahan and introduce yourself.