It is strange-but-true that the systems where safety is most important can often be the ones that are least carefully designed. I thoroughly recommend reading up on the "Therac-25", a radiotherapy machine that would periodically zap patients with doses tens or hundreds of times stronger than intended. Even after a few deaths, the manufacturer was claiming that the software was implemented in such a way that it could not possibly fail. The complacent comments in the current story, where the manufacturer seems more concerned to re-assure their shareholders about their product than to ensure the safety of their patients, seems rather similar.
Start at http://en.wikipedia.org/wiki/Therac-25 and follow the links.