In 1956 during my National Service the Army sent me on a firefighting course at Kent Fire Brigade. One item of training was how to remove the pilot from a crashed jet fighter. They had a dummy Martin Baker set up on which we learnt what not to touch and how to disarm the ejector.
We were also taught about the MiG 15, I think from photos. The Russian ejector was described as highly dangerous, and whilst we were taught a theoretical safe way for removing the pilot, the unofficial advice was "leave him there if you don't want to eject with him".