Qiandu Xiang was utterly confused and couldn't tell if those two ships were the Iron Ten Thousand Bandits', but he could be sure that there were no other ships nearby. That thing must have been released from those two ships at the back. Worried that there might be more tricks up their sleeves, he couldn't be concerned whether it was the Iron Ten Thousand Bandits who released the monster. If they delayed any longer, they would likely suffer even greater losses.
It really seemed like they were coordinating an attack with the Jinglong Hao in front. If they didn't take immediate action and retaliate, their indecisiveness could cost them dearly.