"Oh, no. I’m something called a V.A.D. We work very hard but no one trusts us." (5.34)
Catherine is a Voluntary Action Deployment nurse. She doesn’t have the education of the nurse, but performs all the duties of a nurse. Perhaps this makes her seem even more courageous. She saw pain and suffering, wanted to help, and didn’t waste time saying "I’m not qualified."
"You better wait until the shelling is over." "They want to eat." (9.91-92)
Frederic’s bravery stems from love. There is just no question of sitting pretty when the men he works with are waiting for him. He’d rather die than let them down.
He bit his arm and moaned, "[…] Oh Jesus shoot me Christ shoot me mama mia mama Mia oh purest lovely Mary shoot me." (9.119)
Pain trumps bravery every time.
"Did you do any heroic act?"
"No […]. I was blown up while we were eating cheese." (10.3-4)
It’s doubtful that Frederic ever sees anything he’s done as an act of bravery. He’s not just being humble.
"I hope some will come. […] They will unless there are more patients." (16.34)
Catherine sounds like a coward here, wishing for the pain of others to further her own pleasure. But since she knows that more patients are inevitable, the statement is also brave as it exposes her to Frederic ’s possible disapproval. Especially because he knows she became a nurse in the first place in large part because she hoped her fiancé would somehow be lightly wounded and sent to where she was stationed. Like all of us, Catherine is an odd mix of courage and cowardice.
"I’m afraid of the rain because I sometimes see me dead in it. […] And sometimes I see you dead in it." (19.137-138)
When we know how truly scared Catherine is, it makes her seem even more courageous.
"The brave dies perhaps two thousand deaths if he’s intelligent." (21.92)
Catherine suggests that every act of bravery requires the sacrifice or death of something inside the brave person. She also connects bravery to intelligence, suggesting that it takes more than raw courage to be truly brave, that sometimes bravery means thinking in a brave way.
"I feel like a criminal. I’ve deserted from the army." (34.114)
We don’t know if Frederic ever gets over this feeling. We can see that if he hadn’t deserted, he would probably be dead, but Frederic isn’t sure it was worth it. He possibly even thinks Catherine’s death is punishment for his "cowardly" act. Interestingly, he has sympathy for other "deserters," like the man who is on the run and afraid to seek medical attention for his hernia because he thinks they will send him back to the battlefield.
If people bring so much courage to this world the world has to kill them to break them, so of course it kills them. (34.81)
"I’m not brave any more, darling. I’m all broken. They’ve broken me. I know it now." (41)
This is confusing, because what’s breaking Catherine is the process of childbirth. It’s not clear who the "they" is that she’s talking about. It’s possible that she’s talking about people in her past, of whom we, and possibly Frederic, know nothing about. "They" could also be Catherine’s personification of the abstract forces working against her.