godbless

I was flying from Montreal to Beijing last month and I was in the bathroom during the flight. The alarm rang randomly, I got out of the bathroom immediately and the attendants checked the bathroom and myself. They suspected me of smoking in the bathroom which I obviously did not and they let me back in my seat because they did not find anything in the bathroom or myself. I got off the plane with no other inspections in Beijing and got to my destination which was Korea. However, I had to go through a secondary inspection in Korea and they checked my bag and my luggage. I did not have anything I was not supposed to so I went out the airport safely. I was just curious if the secondary inspection was caused by what happened during my flight from Montreal to Beijing. I am flying back to Montreal in a few days and I was just wondering if I will go through the secondary inspection again in Montreal. I never went through secondary inspection my whole life while I was travelling around the world and also I saw somewhere that my name could go in their system for any reason and this can lead to secondary inspection whenever I am moving around the world. I am just looking for some opinion because I do not think anyone can give me a definite answer. I also do not think I will get an answer at the airport either. Please give me some opinion!