A More Permanent Hell - S2-E20
Factual error: In the first scene, Dr. Dana says the asteroid heading for Earth is 5 miles wide, "larger than the one that caused the dinosaur extinction." The asteroid that did in the dinos is estimated by most scientists to have been 6-8 miles wide. (00:03:00)
A More Permanent Hell - S2-E20
Revealing mistake: Mt. Vesuvius is erupting and LaCroix's villa is collapsing around him. But while the ground "shakes," statuary falls over and the walls cave in, look closely at the fountain/pool in the center of the room. There's not a drop splashing out of it. In fact, the water's surface is smooth as glass.
Answer: Nick was sick and tired of being an immortal bloodsucker. He wanted to be human, fall in love, get married, have children, grow old and die. As for Janette, according to her, she fell in love and the passion she felt "cured" her of her blood lust.