When I took the bar exam, we were seated on long benches with a dozen people. A woman at the end of my bench had a complete breakdown during the test. She started quietly weeping, then after about half and hour was sobbing, and finally was crying so hard, shuddering and gasping, that she got up and never came back. I felt terrible for her.... the bar exam is brutal in the best of circumstances (two full days of super-high-stakes testing), but some people are taking it the third or fourth time, and for them it's even harder.
Anyway, when I see a breakdown like that, I try not to judge too much, because "there but for the grace of God go I." Mental stability is something most people can take for granted, but you never know when the wrong cascade of brain chemicals could hit you, too, or when life might deal you just the wrong kind of one-two punch,k and suddenly you aren't as stable as you thought you were.