He longed to ascend through the roof and fly away to another country where he would never hear again of his trouble, and yet a force pushed him downstairs step by step.
Sense of escape! This is a really important quote to recognize! It demonstrates Doran's obsessive longing to flee the small world of Dublin and discover what more the world has to offer! His "trouble" reveals far more than his conflicting decision to marry Polly, and instead alludes to the troublesome situations that people throughout Dublin are undergoing in their confusing political and religious circumstances. The "force" that pushed him to meet with the Madam and be put in an uncomfortable position is the harsh reality of how people throughout Ireland felt about dismissing opportunities that could be potentially life-changing.