Saw a document on Cold war and getting own spies out of some countries.
They developed the pick-up system , and I always thought it was only in a Bond movie.
Those who "volunteered" to be picked up during the development phase were truly brave, I think. According to the document the first two or three died because their soft tissues especially the bowels/stomach could not take it.
https://www.cia.gov/library/center-f...952201373.html