Of course the all important rule is all on board is tohydrate well, something the crew discovered toward the end of the first leg of the journey, when water levels on board were so low not enough could be spared to keep the on-board hydroponic garden alive.
As his company lies incapacitated by dehydration, as weather and geography prevent resupply from helicopters while the company is pinned down by North Vietnamese troops, the captain orders the medics called "squids" to pull the IVs from the wounded in order tohydrate the "effectives" functioning soldiers so that they can survive the next assault by the enemy and continue the mission.