I believe the transfer of SGT Hernandez was the correct decision. There is definite risk with removing a seasoned PSG from the platoon and someone who the platoon is familiar with.  The fact that they are in a combat situation makes it even more risky. The PSG knows how the platoon will react and what decisions need to be made. But like any position in the military one person will leave and someone else will come in to replace. The removal needed to take place because LT McDonough had lost his trust in SGT Hernandez. Trust is a very important thing between a PL and the PSG. The PL cannot question what the PSG will do in his absence and needs to have that trust at all times. The chaos of combat needs that trust as well. Lt McDonough cannot hesitate on decision making because of a lack of trust within the leadership of his platoon. That can cause soldiers to lose their life in combat.