how does a void elf get back home

Once the void elves are inside the workshop, they should have a way to communicate with the other elves. You can try tapping on one of the elves on the shoulder and asking them for help. Alternatively, you could walk around and see if there are any elves working nearby that you can ask for assistance. If all else fails, you can shout out loud and hope that someone will hear you and come to your aid.