Real combat=/=Modern Warfare 2 campaign.
I know two people who were in wars. My grandfather was a medic (he was so good that his patients felt 150% better), and he saw a lot of chaos. Fortunately he's still alive.
The other guy, however, wasn't so lucky. He was our school janitor, and he gave a speech in front of the school about his time in vietnam. A 5-year-old threw a grenade at him, and he saw fellow soldiers impaled on posts. Oh, and he's dead now. The cause was Agent Orange, a carcinogenic herbicide. It gave him cancer. He died 2 months after giving the speech.