The members of the Tianying Gang retreated, but they didn't go far because they were afraid that the explosion made by Gu Ning would cause a big fire. If they didn't put out the fire right away, it would damage more facilities. And they would be severely punished if they left it behind.
In the end, they figured out that "Tang Aining" simply wanted to do damage and had no intention to hurt people. Therefore, they waited in silence at the parking lot outside the bar. Although they heard the noises, they weren't able to hear them clearly.
According to the sounds they could hear, they believed that "Tang Aining" didn't use explosives, but damaged the bar by smashing things. In that case, the damage to the bar couldn't be very serious.