Action is a major defining feature in A Farewell to Arms. But, because the actions we see have multiple and sometimes conflicting implications, they serve to make the characters more complex and open to interpretation. When Frederic leaves the retreat without permission, he can be seen as a deserter and/or a good lover to Catherine. When Rinaldi moves to kiss Frederic we can interpret it as erotic and/or platonic desire. When Miss Van Campen gets Frederic sent back to the front, we can view her as vindictive and vengeful and/or dedicated to her beliefs.
Booze is a huge part of Frederic Henry’s life, during and after his time as an ambulance driver. His drinking makes us question his reliability. We can’t think of Frederic without a drink in his hand. He usually even drinks wine with his coffee! How you personally feel about drinking, and particularly Frederic’s drinking, determines how the drinking characterizes Frederic in the novel. At the very least, it characterizes him as a potentially unreliable narrator. That is, if he was drinking that much during the events described, how can he remember them accurately? Yet, there is also the suggestion that drinking keeps him calm (like before Catherine’s death), and therefore makes him a more reliable narrator. If you buy this, then the drinking might characterize him as a man dependant on alcohol to keep his cool.
The main characters in the novel share a common occupation. There are variations, but they all work at healing the sick and caring for the wounded. Rinaldi is a surgeon. Frederic is an ambulance driver. Catherine is a Voluntary Aid Detachment or V.A.D. She isn’t a nurse but she volunteered to go to Italy and work as a nurse. And the priest is, well, a priest. These are all occupations which center on healing people who are physically or spiritually wounded. In the context of the novel, there is also lots of risk involved in having jobs like these. The occupations of these characters tell us that they are kind and brave. They want to help others, and are willing to take huge risks to do so.