Sigh
They didn't die because of the explosion. It was the cause of their death, yes. There was an explosion which closed up the tunnel
Remember when they were in a tunnel reminiscing about past? Saying it was really nostalgic and fear mongering even though they never feared the dark at all
They found each other in the tunnel (I fucking hope) but it was so dark they couldnt see each other faces. My guess is they died due to landslide or lack of basic necessities (food, water, etc)
It was the post war era so not much advance with technology, so I think there's no proper machine and tools to dig up a hazardous tunnel and save people

I read it. I kind of dont get it, how did they die in their past life?? Did the uke(in the past life) left him to work?? Pls help!!!