When Victor ran in fear, he left behind a sweet monster in need of a guardian. Victor said “… I will cause fear”. Victor caused fear in himself; he ran out because of how Frankie looked, he didn’t care about what he was capable of doing. Victor didn’t realize that all Frankie wanted was someone to procure. But instead, he left society to assail him.
A noble savage is a character in a Romantic literature ---like Mary Shelly’s Frankenstein--- who embodies the concept of an idealized outsider who has not yet been corrupted by society.