Law schools go strictly by the numbers. They calculate an index based on your undergrad GPA and LSAT, and essentially make 90% of their admissions decisions based on that index. The rest of the application is just window dressing to make sure applicants are motivated to jump through the requisite hoops.
Med school is different, in that they do look at all the pieces of your application. Due to the sheer number of applicants for limited spots, there is a significant element of randomness. However, the GPA/MCAT numbers do matter in the aggregate. For example, if the rest of your application (recommendations, extra-cirruculars, etc.) is up to par, and you break 35 on the MCAT, you will most likely get in somewhere, assuming you apply to enough schools and get your apps in on time. There are just no guarantees where. You could get a 40, get rejected by Albany and GWU, but get accepted to Hopkins and Duke. Go figure.
On the other hand, if you score below, say 30, you may very well be wasting your time and money if you decide to apply to too many of the top MD schools (e.g., Harvard, Hopkins, Stanford, Yale, WashU, etc.), unless the rest of your application is truly extraordinary. Nothing wrong with a reach, just don't blow your budget on reaches. But you still have a shot of getting in somewhere.
Look at mdapplicants.com; you can screen by GPA and MCAT. What you will learn is that most people, even those with the best numbers, had many more rejects than acceptances. Of course, you only need 1 to say YES.