A deploying Marine is trained to expect the unexpected. That’s fine — but it’s still frustrating when it comes because of incompetence. This week’s Marine Corps Times cover story takes a look at a deadly firefight aboard Musa Qala District Center, a forward operating base that served as the battalion headquarters last year of 1st Battalion, 2nd Marines, out of Camp Lejeune, N.C. Marines with 1/2 found themselves in an unusual situation on Aug. 7, 2010 — fighting an insurgent loose on the base. He’d busted loose from a detention center on base run by the Afghan National Police. This…