Story
Elvida claimed the only way to escape this place is by reaching the cave beneath the lake and ascending as a Daeva, stressing that you must trust her.
After completion (spoilers)
"There is still a place in Ishalgen where you can go through Ascension." Elvida insisted that the only way to escape this place was to reach the cave beneath the lake and undergo Ascension as a Daeva. Urging you to trust her, she revealed the location of the hidden sanctuary. Following Elvida's instructions, you set out for Tunapre Lake.