In Aztec warfare, most cities were conquered fairly quickly. However, better defended locations did take longer. Hassig particularly notes that the length of time dedicated to the attack depended on the intensity with which the goal was desired (Ross Hassig. Aztec Warfare. University of Oklahoma Press, Norman. 1988, p. 105). In this case, Shiz has already demonstrated that the goal is highly desired. This will be a war to the end.