The increase in the number of criminals represented a significant shift for the special task force.
In the current situation, the criminal Zhang Hai's escape wasn't really a big deal. Criminals are bound to run, and they do so for their lives, naturally exhausting all means to flee, to reach their limits, to display their cunning, to run with the romance of spring rain and blood, even to the point of bloody urine.
However, the situation changes with the addition of one or more criminals.
Firstly, the case became a gang-related crime; secondly, the task force had no grasp of the second criminal's situation, nor could they tell who the mastermind was and who was the accomplice.
The latter was particularly serious. If they closed the case here, and then found out that another criminal was the mastermind, the situation would become quite awkward.