Just a few thoughts, while the grill heats up:
Anyone can snap.
From the movie, "What's your costume, Thursday?" "I'm a homicidal maniac - I look just like everybody else!"
Shrinks are purported to suffer from mental illnesses of indeterminate degrees. Does this mean that to those who evaluated her, this woman seemed completely normal to them - ergo, having a transparent/congruent illness?
Are there repurcussions to demanding flawless conformance to an artificial standard? The brass ring, getting to ride into space, could easily see anyone forget who they are, maybe?
Maybe this is proof that even astronauts are no less fallible than any other outstanding representatives of humanity - history probably has countless examples of the fallen hero. From Frank Herbert; "We did but build his pedestal, a narrow and a tall one."
Cheers.