I think they would have spent time mourning if it wasn't for the fact that they had soldiers pointing guns at their heads every five seconds. War's a bitch.

Although Chapter Two spoilerwe do find out that they seem to have some kind of massive lack of feeling towards death and that they apparently forget people fast or something like that, so I imagine this is a large part of why they were so blank-faced about it all. Although it does leave me really wondering about Izana, and what got him to the point that he had so many feelings about his death. I get the feeling death is going to be a huge theme in this game after the cemetery scene.