The strengths and the enigma of the 2nd part of Halliday's Asymmetry

First of all, I think the second section of Lisa Halliday's debut novel, Asymmetry, is good, in fact far better than the first section whose main interest for me (and I believe for most readers) comes from its portrayal of a character who closely modeled on LH's friend, Philip Roth. The second section is about a young man, Amar, born in Iraq but raised in the New York area, a Ph.D in econ, who is returning to Iraq (in yesterday's post I said Syria, my bad) to visit his older brother, a doctor, whom he has not seen in about 10 years. This section alternates between passages that give us Amar's back story - his faltering relationship with a young, ambitious, American-born woman who switches out of a drama major to go premed, Amar's time volunteering in a children's hospital in London, a previous trip w/ his parents to Iraq involving a long desert crossing by car through scary checkpoints - and the present time at which he is held, interrogated, and basically humiliated at passport control at what seems to be Heathrow. Halliday shows off all her strengths in this section, not only her ability to create a tense scene and keep to keep the story moving, but also an amazing assimilation of knowledge, including much about war correspondents, life in Iraq during war, medical science, bureaucracy, and more. She does have an annoying way, though, of dropping in just enough info for we readers to "decode" and to feel smart because we did so (e.g., Amar's brother we learn in an aside revered a pianist who grunted and groaned while performing; why not just say it's Glenn Gould?). I'm still not sure of the overall meaning of this section, however: Are we meant to feel outrage at this tight passport-control procedure (I feel it's necessary and I'm glad they take such precautions; many might disagree, as see Alie Smith's recent grumpy novel about UK bureaucracy, Autumn). And I'm still befuddled as to why this is a novel and not a 2-story collection. Is this meant to be an asymmetrical response to the first section: One section follows closely the most basic advice to young authors, write about what you know, whereas the 2nd section is the complete opposite - a narrative that, though contemporary,  seems completely apart from the life (gender, nationality, lived experience) of the author.