Endless entombment in automatic door

Construct three adjacent Automatic Doors, powered but without automation, such that on the end opposite duplicants, the door has a 1-tile gap beneath it.

Assign a duplicant to construct a tile in the gap. As they try and pass through the doors, their head will become stuck in the third door. Any duplicants who come to deconstruct or toggle the door will also be trapped. They can be freed by deconstructing the middle door before the third - so long as you don't leave the deconstruct running to go check something else and trap your whole colony...