it is not. the archaic definition of the word might be, but as used in modern language it means something extraordinarily great or intense (implying a positive context in both cases) and I don't believe the author is using a positive context

The Head.

its actually a pretty common thing to happen when traumatized. it's a kind of overgeneralisation. It's like someone being bitten by a dog once and then being scared of dogs for the rest of their life. being a kid just makes it worse. she has to rationalize why someone would hurt her and battle type systems were the perfect excuse in her mind