A more appropriate and correct evolutionary theory is kin selection. Kin selection hypothesizes that individuals conduct themselves in such a manner that ensures a survival of that individual as well as those related to it. Hence, the emperor juvenile looks out for itself, and it most likely makes every effort to attain a central position in the creche and keep it. They're certainly valid questions and may even present caveats to the theory. Simply, fighting is always a last resort in animals.
Most animals undergo extensive and ritualized displays to exert dominance before fighting.
Most of these displays result in one of the two backing down. That solves part of the question. With temperatures below -100 and the scarcity of food, fighting is expensive energetically and repair may not be possible under these winter conditions. An Introduction to Behavioural Ecology. The Discovery of Evolution.