what does it mean "play someone off of someone else "

Ex: "He's learned to play good People off of bad People off of good people"

what does "dial turned up to 11" mean ?
Gotham has always been a city with the dial turned up to 11.

Question

what does it mean "play someone off of someone else "

Ex: "He's learned to play good People off of bad People off of good people"

what does "dial turned up to 11" mean ?
Gotham has always been a city with the dial turned up to 11.

Answer

It means to bring two people into conflict for one’s own benefit or enjoyment