This is foreshadowing Jin’s death.
If you notice, the angle that his car is placed at during the very last scenes, it looks as if he’s parked within the water and all you hear are the sounds of the ocean.
This could very well be how Jin dies. The camera then focuses on the frame of the car, and small drops of water can be seen. This could be from the waves splashing against his car.
Whether Namjoon died within a gas station explosion or he has moved away, Jin is still left alone, and with that, he lets himself be swept away by the water.
Omo, it took four parts but it was worth it!!! Like I had said before I take no credit for this, I only shared it with you all. Also can you help me out of ideas to do for cards. I'm not very creative and I can't think of things to do.