You make some good points and to add to that there was a study where they used radioactive mercury to place fillings in sheep and monkeys and the resulting imaging showed CONCENTRATIONS of mercury in just certain areas of the body.
His theory is just plausible and perhaps just another contributing factor. I always felt it had more to do with the hypersensitivity of certain individuals due to do the burden of existing toxic loads and compromised immune function. One could even make the argument of the placebo effect where as the person expects to have a severe reaction from reading these horror stories on the internet and the mind in its infinite power furnishes them with real physical symptoms (perhaps to the point of releasing mercury from stored sites in the body?). Amalgam fillings are routinely drilled out and replaced in standard practice and I have never heard these complaints from patients in our clinic or heard of the problem until the recent holistic removal technique came in vogue.
You mentioned in a post above over the high speed suction not being used. Yes, the assistant is to hold that near the drill site as standard procedure. When I had mine removed 3 months ago I didn't get the benefit of suction either as the lady dentist I use doesn't have an assistant. I suffered absolutely no ill effect that I noticed but perhaps it was due to the fact I was not expecting such a reaction. I have always felt the body follows the minds expected outcome even to the point of ignoring reality. This is why you hear stories of 100 pound women lifting incredible weight off their trapped children and a three legged dog doesn't accept a handicap. Perception often is reality.
Thanks for your input, I have an appreciation of critical thinking.