This is a well known problem and is included in every mandatory MRI safety course that all medical personnel take. YouTube videos of engineers intentionally sending objects into the magnet like oxygen tanks, stretchers, IV poles.
My sister told me of an incident with MRI machine. Person walked in the hallway by a MRI machine He had O2 tank in his hands. The door to the MRI machine room was not locked and the tank flew out of his hands into the room. The person in the machine was serious injured.