A little battleship had just thrown the festered army into disorder. It transpired that Hao Ren's analysis of the offshoots of the Mad Lord was correct. They seriously lacked intelligence. Even if they had one, it had all given way to the violently destructive tendency. If there were a more 'attractive' and threatening target appeared within their perception, these almost instinctive monsters would immediately shift their attention and started a meaningless pursuit.
This diversion tactic was not a panacea, however. The reason why the festered army was an army was that they still retained a minimum level of concerted action and coordination. They would show interest in the new target within their range of perception, but they would not give up their original target.
The encirclement around the celestial wreckage was only experiencing chaos and disruption, they did not pursue the Petrachelys into outer space.