"Anyways, the story does seem off now that I think about it, because they don't TURN on the thing until you're in there."
MRIs take a considerable amount of time to come to full power and become stable, so they are generally kept powered up for long periods of time.
Depending on the procedure, if it required a higher level of magnet strength, they may well have been increasing it prior to the procedure.
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza
Baby Jesus cries when the fat redneck doesn't have military-grade firepower.