London car bombs perpetrated by Doctors

The most disturbing thing to emerge from the attempted car bombings in London is the fact that several of the perpetrators appear to have been doctors. For people who have dedicated a good part of their adult lives to treating the sick and wounded to turn their efforts to maiming and injuring the very people they treat is hard to believe. Did they walk out of the hospital after a day of helping people and think that blowing up nail bombs in central london somehow aligned with their lives. Only something as ridiculous and dangerous as the notion of a greater God that the answer to could give that scenario even the remotest credence. On a separate note it seems that fortunately the bomb design was incredibly poor. Seemingly created by people who had watched too many movies and not studied enough chemistry. From the publicly available information and the debate on the internet it appears that the best case scenario for the terrorists would have been a large fireball with little explosive power. There was no oxidiser, meaning that there would be no explosion. This is really simple A-Level chemistry, surely doctors are smarter than that. Was there some other motive or were these guys really the Beavis and Butthead clowns they are being portrayed as in the more enlightened security blogs. More from a doctor, from Bruce Schneier, and Danger Room