Understanding of the doors

I wanted to write about how Mohsin Hamid introduced the doors throughout the book. The first time we see the doors is in the women's bedroom in Australia. I was so confused when I read the passage because how could this guy just come out of a closet. I re read the passage a few times because I thought I missed something. Hamid has a few more random door scenes in the beginning of the book and I was still confused. When Nadia and Saeed go through the door I was still very confused. I also re read that a few times. It wasn't until they left the Island and went to England that I got that it was a portal they were going through. I had one of those "mind blown" moments and all the prior door moments made sense all of a sudden which was really satisfying.