Harry Lime knows the consequences of his penicillin racket. He excuses himself with a puerile kind of logic - 'nobody thinks in terms of human beings. Governments don't, so why should we?' As Popescu might say, he has no sense of 'duty' or of 'citizenship'. This is certainly how he appears when he speaks to Martins on the Great Wheel. He appears as one who has not grown up, who lacks a sense of responsibility - Anna and Martins both testify to Harry's Peter Pan -like youthfulness. He even elicits a sort of sympathy, for he seems not to understand that what he is doing is really wrong. He is charming with a child-like naïveté. But this is an act. Beneath all the charm and the wit, beneath his little lectures on war and Michelangelo and peace and the cuckoo clock, lies what Greene describes as a 'melancholy... a memory that this life doesn't go on'. It is the realisation that what he is doing is morally wrong.
Harry is like a child whose self-interest is not mitigated by any consideration of others but who is grown up enough to recognise ultimately that what he is doing is wrong; who hides from his conscience behind a screen of jolly nonchalance and warped logic. He is a good example one who understands the importance of the human act. The vigour with which he tries to hide such an understanding is a testament to that understanding.
The porter is in some ways similar. He does not give evidence at the inquest in order to protect himself. But, unlike Harry, his conscience eventually gets the better of him - 'I'm not a bad man, mein Herr. Not a bad man.' [57] - and eventually gets him killed. In this respect, you might say that Martins is lucky despite Calloway's assertion that he was '... born to be murdered' [81]. But then, as he replies to Calloway at the end of the book, 'I haven't won... I've lost' (134). He loses someone that he loves. Not only that, he is the catalyst - it is he who precipitates Harry's death; indeed, it is he who eventually kills Harry.
Martins' motives are initially to save Anna, who he loves more than Harry and who doesn't deserve her fate in the way that Harry does. She refuses to be 'the price' for Harry's arrest but Martins finally agrees to help nevertheless. Again, we are impressed by the importance of the human act. The tortuous agreement- refusal cycle through which he goes before finally agreeing to help show quite how important this one act is. It is, finally, Martins' sense of social duty that persuades him.
Anna acts as another point of comparison. Harry will sacrifice innocent people for the sake of his own interests. Martins sacrifices Harry - a guilty person, but one who he loves - for the sake of justice. Anna is no stranger to Harry's guilt. She knows what he does and knows that it is wrong. Though she wants no more to do with him, she is not prepared to sacrifice him for the sake of her interests. Of this trio, only Harry can really be judged guilty. Neither Martins nor Anna do anything wrong. They all, however, expose the importance of the human act - individually, but more clearly when their actions are contrasted against one another. A comparison of Martins and Anna shows that it is impossible to categorically define what is the 'right' course of action to take. We cannot be so specific.