I'll go ahead and save xmsr3 from writing a 3 page rebuttal (and everyone else from reading it):
I think he was just trying to put ruiner at ease in case he absolutely couldn't make it, and was in no way implying that being late is acceptable in the military, or for any interview.
Affirmative, but since the trains are rolling at 5, this is no longer an issue.
To any group 3+ members, remember to follow the military mindset.
Hope for the best, plan for the worst
Logistics, first second and third
Always bring to bear more than is necessary, better to have and not need than need and not have
In the case of the USUHS interview, make sure you google map where the school is, where you are staying and how to get to the school (from Reagan to the medical center metro is indeed 1 hour but it does take 15 minutes to get to USUHS from the metro and you need to pass through security, so have a printout of your invite and ID). Print out the maps, know how long it will take and double those times just to be safe.
Try to arrange to come to campus the day before so you can scope out where the buildings and especially where you will be checking in.
Check in starts at 730 but the office opens at 7 and you do need to drop off and fill out some minor paper work. Keep in mind that there are not enough chairs in the conference room for everyone so come early to both get a spot and to get to know your future classmates.
Trust me, being able to walk around, getting used to the uniforms, (for those coming from a civilian background) and learning where all the buildings are, as well as talking to your fellow applicants, especially the prior service ones, is invaluable towards putting you at ease, gaining valuable info and having a better day.
Good luck and I look forward to hearing how things go today.