My OS X crashed during a 'hung' security update

Yes, it happened to me to .. a solution to reapply the patch, see below:
http://blog.washingtonpost.com/securityfix/2006/04/apple_issues_another_round_of_1.html

Luckly Apple is UNIX based; Sadly, the Apple supports do not seem to take advantage of it and tried to resolve problem Microsoft Windows way - to 'always' ask users to re-format the harddisk and re-install.