It takes a very specific type of person to get scouted as a WW2 codebreaker and then decide that doesn't involve enough violence for her taste and go do something more dangerous instead.

Charismatic, skilled at hands-on mechanical/combat type tasks, low end of species literacy, very poor impulse control, prone to latch very hard onto people who credibly display signs of caring about him as an individual.

Personality very significantly mutable by environment.

They're supposed to template together. Problems will naturally appear when you have some without the others. :)

('Together' can here include Jay/Hermes Grey, a subtype of James-and-Sirius who is one guy instead of two guys who are kind of one guy.)