"My understanding is the method of drilling plays an important roll in contamination during extraction. Any comments?"
Drilling is NEVER used during the extraction of teeth. However in the removal of fillings a drill is used to remove the amalgam. Instead of completely drilling away the Amalgam the dentist will drill a thin slot across the filling and use an instrument to pry the remaining Amalgam free from the tooth. You may now rinse and spit (chunks).
You need to appreciate the drilling on a molecular level. While it is easy to assume the tiny drill tailings may be half mercury and the other half silver this is simply not the case. Even the microscopic tailings are still chemically locked into Amalgam just the same as the whole filling is on a larger level. The release of mercury VAPOR during drilling is very minor and the use of high speed suction which is standard procedure negates this to nothing.
It is a shame the fear of not being able to find or afford a high priced holistic dentist prevents so many people from getting their Amalgams removed. Fear of the dentist is why some fillings are very large as it took overwhelming pain to even get them to go to the dentist. Now fear again prevents people from getting them removed because they can't find the RIGHT dentist. Fear is the number one cause of poor dental health in my opinion. Just do it!