The lego technic box houses a motor and battery box and is covered with the foil tape over card. There is an easy access flap that allows me to get in and replace the batteries. I used a technic heavy duty clutch to allow the motor to be wound up whilst off, and still spin when on. The clutch also prevents damage to the motor and axles when it gets caught. The key is too heavy to rest on a single technic axle so I used a heavy duty lego technic turntable.
Lastly, i needed a way of concealing an on/off switch inside the mechanism, so i made a rocker switch out of Technic elements that is hidden beneath the card. Enough pressure on the card will push the rocker switch without damaging the outer finish.
In future, what I may do is use neodymium magnets with a plate underneath the corset for easy on/off. Going to the toilet is difficult in this costume!