In this case Erik WOULD be using it after promising he wouldn't with the women going to TC thinking they again snared another guy in their web then Erik lights a fire under everyone's butt and decides he will use it with causes everyone to panic/scramble.
I don't see Erik getting the idol unless he wins RC and exiles himself. If he had it, wouldn't he keep it secret and try to idol Amanda? I think he wins immunity (male-friendly IC), but somehow Natalie and Cirie use has greed to get Amanda out against him.