There is a teleporter that will take you out of the ruins, to several different destinations.
It's even labelled on your automap as the "Teleport Room" if you haven't found it.
First, you have to find the room. It's hidden near the Dracoid Mage Tower.
Look for a secret entrance on your map.
The controls to open the door are nearby.
Have you noticed all of those globes around the ruins?