Honestly when I saw this I thought Vietnam, the meat grinder representing the mass amount of drafting done by the United States, the alien representing the people sent to a foreign country to die in a cause they did not believe in. The wall represents the sense of never being able to go home, that yearning you get when you know there is nothing left and that you will literally die where you are. The mask can represent a lot at the time, either the fear of breathing that was instilled by the airdrops, or even Agent X. The eyes being so wide seem to say that the person knows whats happening, but isn't able to say or do anything to stop it. The hand touching the wall is that final moment when they say to themselves "This is how it ends. I did what I could, and there wasn't anything else I could do."
OR it could quite literally be what Jarvin said, I read that right after I wrote all that, but it tied in pretty well.