Final answer:
In case of an emergency quench of an MRI machine, the correct action is to walk calmly towards the exit to avoid any additional hazards created by running or the influence of the magnet.
Step-by-step explanation:
The question seems to be describing an emergency situation involving a Magnetic Resonance Imaging (MRI) machine; thus, the term 'quench' refers to a sudden loss of superconductivity in the MRI magnet, which can create a hazardous environment. In such an event, the correct answer would be B) Walk calmly towards the exit.
This is because running might create additional hazards, and it is important to move away from the magnet in an orderly manner. Using an elevator would not be advisable, as it may not be operational during an emergency, and staying in the room or running towards the magnet would be hazardous due to the potential release of cryogenic gases and magnetic forces.