Dr Sohn was a human scientist.
She was part of the Golgotha Project. When there were indications of destabilization in the Lychburg area decades after the Project had been closed, she and Major Joel Haasterman were sent to investigate.
Sohn stayed with a small team in the observation bunker near the site to learn more. When Lychburg started to return to this dimension, the bunker was evacuated but she stayed behind to see what would happen. She survived unharmed and left the Project.
Dr Sohn gave up all involvement in the physical sciences or any form of mysticism after that. She moved to Minnesota, becoming a teacher of traditional weaving techniques at a small arts and crafts college. (PROSE: Heart of TARDIS)