It's all in one day, unless you're also interviewing for the Cleveland Clinic program. You have six or seven interviews if I recall correctly. There's one interview with the medical school, one with the MSTP director, two with MSTP committee members, one with an MSTP student (really an opportunity to ask questions more than anything else), and a couple faculty interest interviews. Everyone was pretty friendly, and generally trying to sell Cleveland, and Case, to me. No questions were really out of left field - this was a pretty standard interview overall, and generally a good one to have early. There's plenty of good food, and time to interact with students. The school does a good job of mixing up students with applicants - so you'll get to meet first years, sixth years, and everything in between.