In the 1979 movie Alien, in a last ditch effort to kill the alien, Ripley decides to activate the spaceship Nostromo‘s self destruct sequence. This scene always fascinated me because of the design of the controls to activate the sequence. You can see in the scene below that there are several steps needed to activate the sequence.
First you have to press a red button which opens a hatch with a handle that you have to pull. Then you unscrew two screws that let you take a panel off to see to large levers. Then you have to pull down these levers which open up the main activation panel. Then you must follow the instructions to press a series of buttons which then release a bolt that you have to screw into a cylinder. Then you must raise the cylinder and press a button behind a panel in the cylinder. You do this for the other three cylinders. Then you are alerted that the emergency destruct system is activated and that you have 5 minutes to deactivate it or 10 minutes until the ship explodes.
It seems that the complex series of steps required to activate this sequence is designed to convey the gravity of the action you are taking. You can tell that the designer of this system wanted it to be complex enough that it could only be done if you really needed to. The designer made some decisions about the abilities and condition of the user activating this system. First, that they are trained in how to use it. I don’t think just any person would be able to figure out how to activate it unless they were trained how. Second, that they meet a certain physical requirement to do it. You have to be strong enough pull the heavy levers and dexterous enough to unscrew the screws and screw in the bolts. If a person was injured badly, they probably would not be able to activate this system, which is an interesting choice.
The system gives you 5 minutes to reverse the sequence but it is so complex that it is incredibly difficult to reverse it in time if you made a mistake. In fact, Ripley tries to reverse the sequence but is too late. I would not call this a very user-friendly design.
I don’t know if this has any real world applications, maybe with the scuttling of military ships or sensitive hardware, but I think it is an interesting exercise to think about the decisions made in the design of fictional objects.