Some people just aren't ready. We had one that smoked biochem, had a 32+ on the MCAT, 3.9x from a good school and left after neuro. He quickly learned in MSS that he had difficulty differentiating a nerve from a vein and supposedly almost failed. He hit neuro and did not improve so he quit. Had one that didn't survive the first week -- after the "brief review of medically significant chemistry/organic chemistry" which was done in 2 hours, she went to the administration over lunch and quit. But remember, the vast majority pass and graduate. You may not graduate at the top of the class, you may have to pull strings, do a boatload of audition rotations in your desired area and have a serious "come to Jesus" moment regarding your ability to get into the specialty of choice, but most people will graduate if they just don't quit and adopt the mindset of "I will do whatever it takes to graduate". For me, once I started, I told myself that I would either graduate or get carried out feet first but I would not quit.....