She was 'fanatically' devoted to her job.
a religious 'fanatic' [='extremist']
He is 'fanatical about' boating.
(..) That was Karla. He went back to die rather than giving in. Yes, and that's how I k now he can be beaten. Because he's a fanatic. And the fanatic is always concealing a secret doubt. What did he look like? I can't remember. After today, Peter, (..)2011 Tinker Tailor Soldier Spy