Human fear arises from many aspects, such as the fear of the unknown, like this sort of fear where one can only watch helplessly as a close attendant's internal organs are cooked alive and die.
"May I feel the fire poison within your body?"
Out of gratitude to Gongsun Jin, Qin Niu was willing to offer help now that the other party was in trouble, should he be able to provide any assistance.
Moreover, having formed a deadly enmity with the Nine Insect Gang, they would surely not let him off the hook.
The day for battle would inevitably come, perhaps even looming on the horizon.
Given the formidable attacking tactics of the reinforcements brought by the Nine Insect Gang, he definitely needed to learn more. This way, when he eventually confronted those people, he could do so with full awareness.