Once the elevator arrives at the floor, it will park with its doors open and the car buttons will be disabled to prevent a passenger from taking control of the elevator. Medical personnel must then activate the code-blue key switch inside the car, select their floor and close the doors with the door close button. The elevator will then travel non-stop to the selected floor, and will remain in code-blue service until switched off in the car. Some hospital elevators will feature a 'hold' position on the code-blue key switch (similar to fire service) which allows the elevator to remain at a floor locked out of service until code blue is deactivated.