You could also have electrical switches. Ordinary lifts already have a risk of this and already protect against it electrically. Next time you're in a lift, try

You could also have electrical switches. Ordinary lifts already have a risk of this and already protect against it electrically. Next time you're in a lift, try pulling the doors open while it's moving. In my experience, you can fairly easily open them and the car comes to a sudden stop before you have a chance to poke your leg out and get it chopped off.