It's very hard for me to understand how some can do this. I know it's cultural and thus, I won't comment more, because, of course, I am not Japanese. I wouldn't do anything where I was knowingly putting myself in this position. Yes, it's selfish in the eyes of a different viewpoint and I totally understand that.
This was the main argument I had with my son when he joined the military. Why would you do something that intentionally put yourself in harm's way, when you don't have to? Of course, now that he's married, I think he is starting to see this from a different viewpoint.