For high-profile ones, the only example of a quasi-successful confrontation I can think of only through sheer luck avoided an innocent person being shot: http://www.slate.com/articles/health_and_science/human_natur...
For high-profile ones, the only example of a quasi-successful confrontation I can think of only through sheer luck avoided an innocent person being shot: http://www.slate.com/articles/health_and_science/human_natur...
Also, your second paragraph is somewhat ambiguous, I'm not sure if you mean to imply that the incident described is the only incidence of a confrontation with a deranged shooter. That is most definitely not the case. There are many examples of this happening:
http://www.denverpost.com/breakingnews/ci_20457445/2-die-sho...
http://en.wikipedia.org/wiki/Appalachian_School_of_Law_shoot...
http://en.wikipedia.org/wiki/2007_Colorado_YWAM_and_New_Life...
http://en.wikipedia.org/wiki/Pearl_High_School_shooting
http://articles.latimes.com/1992-01-01/local/me-1021_1_publi...
That's not very surprising. Many police officers only practice with their weapons once a year when it's time to qualify.
The average concealed carry permit holder shoots for fun, thus practices often.