Week four begins White Phase, focusing the trainees on the mastery of their service weapon, the M4 rifle; while most embrace rifle marksmanship, one trainee lags far behind, facing the possibility of being recycled back to the beginning.
The trainees return from holiday break to news of an Iranian missile strike on a U.S. base; coming to grips with the possibility of going to war overseas, one trainee must qualify on the rifle range to avoid being sent back to day one.