The infinitive here is 'to leave', and it is used as an 'adverb', meaning 'with the intention to leave', since it modifies a verb, it has to be an adverb.
The tone is more depressing
Hemingway's limited use of adjectives enables us to understand the story at two levels. The first level is that the simplicity makes it easier for us to understand the text itself in its physical form. The second level is the deeper meaning which is reflected in the minimalistic style. Instead of just telling us something, he wants us to understand it on our own, making it a much more lasting impression.
<span>It makes the few descriptive words he does use more vivid and forceful.</span>
B in 1940 racism was still going on