Kirk remarks in this episode that the alien force will have the Enterprise crew and the Klingons fighting for eternity. I can understand the serious wounds being healed quickly with the help of the entity, but how is the alien force going to shut off the aging process? Unless Kirk was anticipating the respective crews having children, and those children fighting one another, etc., but I doubt it. There was no indicator in the episode that the entity had the ability to shut off the aging process, as the Companion apparently was able to, so maybe Kirk was speculating. 
