The first interview of the afternoon starts at 1:30 and each interview is 20-30 minutes. You'll generally have a break between interviews, and will also have a 1 hour tour. Some people have the tour before their interviews while others have it scheduled in between...it varies from person to person, day to day. Assuming there are no hitches, most people are done by 4:30. Even if you had the very first interview at 1:30 and then had your tour at 2pm and your second interview at 3pm, I'd still say that catching a 5pm flight is definitely quite risky given the slowness of the shuttle, potential traffic, etc.