Lesson learned - You can only shoot near an MRI machine that is out of service or has been properly shut down for servicing aka, one that is not in a hospital. Any active MRI (whether on or off) is too dangerous to be near. Perhaps MRI manufactures have dummy models that have no working parts, and you could shoot in one of those.
You could always buy your own MRI.
If the UPS guy can get it out of the truck you know it's safe to use. :)