Since there's more than an 80% attrition rate from pre-med to med school, comparing med students to SEALs would be a reasonable comparison, by way of your achievement relative to your starting group. It's an entirely different type of challenge, but I doubt that was really the point.
Not sure about that statistic...you have a source? It seems mighty high.
But, even, assuming there
is an 80% attrition rate, I know a lot of pre-meds who didn't have their hearts in the whole process and still got in. Sure, they wanted to be doctors, but they scraped by doing the bare minimum. With BUD/S, you have to give full effort all the time, with your whole heart in it, or they'll break you. The BUD/S instructors literally have hypothermia tables memorized so that they can keep the students immersed in the ~55-65 degree water as long as possible. Seriously, just to get an understanding of how bad that sucks, go take a shower with the water as cold as it will go. That's what I did--I was watching a video of a cold water swim they were doing, and watching it on a screen, it looked easy. So I took a 10 minute shower as cold as it would go. Wow, talk about a wake up call.
And then there's Hell Week, where the students go from Sunday night to Friday afternoon with only 4 hours of sleep the entire week, doing physical evolutions (their word for a specific training exercise, like a mile swim, for instance) the whole time. They have to use their mind to push their body beyond what they thought was possible, when they're in pain, cold, and tired, with skin that's raw and chafed, and instructors are taunting them to quit and go take a hot shower. I never even came
close to that level of effort/commitment as a pre-med. There was never a point where I thought, oh, I might have to quit, it's too much for me. SEAL training and med school are very different, yes, but SEAL training is exponentially more taxing than studying, going to class, etc. Comparing some dorky pre-med student studying for an o chem test to a SEAL is insulting to to the SEAL.
(Didn't mean to write a novel, but I have a ton of respect for SEALs and what they do, and the whole process of their training fascinates me, seeing how far a human being is able to push themselves).
Edit:
http://www.youtube.com/user/MrHastyAmbush#p/u/61/68EEiuztDoo
Skip to 6 minutes and watch the fun ensue. That's just one tiny, tiny fraction of their training--but it gives you an idea of what they go through.
Edit 2: Skip to 12:30 if you don't want to watch very much. Instructor: "What's six times three?" Student, ~10 seconds later, cause he's borderline hypothermic: "18." Instructor: "Ohhh, you're a brain surgeon." Love it!