Anchor: But, even as he did so, he felt himself seized from behind in a grip of iron.
Entailed: He was grabbed from behind with an iron grip.
Contradiction: The strong grip came from directly in front of him.
Contradiction: No matter what your age is, you can call your boyfriend, "boyfriend". 
Contradiction: I have two reasons for including it here, both beneficial.
Contradiction: The valley is noticeable almost immediately. 
Contradiction: There are people drinking outdoors.