The Hittite Empire lasted 1650-1180 BCE, and Derinkuyu is estimated to have been built between the 8th and 7th centuries BCE, not 3000 BCE.
If torches and candles couldn't burn in those underground tunnels, humans couldn't exist there either.
Humans require sunlight. Our bodies have photoreceptors that respond to sunlight and convert it to energy
You're thinking of chlorophyll, which only occurs in plants. Humans can exist quite well without sunlight; consider the people living in Norway or Alaska, among others.
Is Bennett experiencing some form of dementia? I looked all this up inside of 10 minutes.