Well, I had an injection & didn't feel a thing but I was conscious all the time... Only had 1 amalgam removed at a time.. which I think is better than having all at once..

I had previously worked on my fear of dentists with EFT, TAT & such, & building myself up with some positive statements etc (like 'He knows what he's doing', 'He's an expert' etc)

Actually I think it's better if you're conscious, cause you can see what he's doing.. I was shocked to see him not use a dental dam!! (I was seeing a 'normal' dentist, not a natural/mercury-aware one, though! But he was said to be 'very good' so actually I was quite shocked!!)
But at least I asked for water to rinse & spit it out!!

If I were 'put out' I would want the whole thing to be recorded on camera &/or someone trustworthy watching all the time.. & of course things well-discussed in advance, so there would be no surprises.. (I really wish I were smarter about this & discussed it more in advance!)