What did Bartle think about when he looked at the battalion scattered throughout the plane from Germany?

When Bartle looked at the battalion scattered throughout the plane, he wondered how many did not make it. He remember that three specialists from Bravo company had been killed by a suicide bomber in the mess hall. There were other killed over the year. He remember that one person from HQ company was killed by a mortar on the FOB, and he had heard that another was killed by a sniper. He tried to remember if it was ten or 20 that had been killed.