I have a similar issue, except, instead of Tartarus, I can not exit Auntie Cleo's Secret Lab. The front door, side door, and vent exit all lead to an instant crash as soon as the outside world loads in. I hope our issue can be patched.
EDIT UPDATE:
What I did was open my GeForce video driver manager and install the latest ones. It turns out my video drivers were 2 years out of date. I can now leave the lab just fine and have not seen anymore crashes for a while. I hope this helps everyone else with GTX970 cards.