Reading more about the story I wonder how much of it is true

You can't just "walk into an MRI room", for one

When the MRI is working you definitely can't just walk in. Nobody is in there because of the radiation, so i doubt they just have an open door policy

Then, when there is an emergency like, you know, someone being strangled with a 9kg necklace on his neck by the machine's magnetism, you can press the kill switch that will quench the magnet by venting out all cooling liquid. This will damage the machine and is also a very expensive little joke, but it would save the life of that guy. Why didn't they do that?

It's a similar story to the guy that went into an MRI with a gun, causing it to fire and kill the guy.