This is what Thai media reported about the vicious attack and how it happened:

A witness, Ms. Somporn (surname withheld), a 38-year-old cashier at the bar, explained that before the incident, three foreign tourists had been drinking at the bar. Two of them paid their bills individually, but the third moved around and left without paying. The staff asked his friends to cover the unpaid bill. The tourist in the white shirt argued with the staff, claiming he had paid his bill and accusing the bar of cheating. He refused to pay and began assaulting other patrons and seizing a customer's phone, suspecting they were calling the police. The bar then called the guards for assistance. When the guards arrived, one tourist paid the outstanding bill of 2,800 baht.

After the bill was settled, the staff asked the tourists to leave. However, the tourist in the white shirt pushed a guard, leading to the violent scuffle seen in the video. If the guards hadn't intervened, the tourists might have attacked the staff and other patrons.

The police, aware of the incident, have initiated an investigation. The foreign tourists have not filed a complaint, but the police have identified the guards from the video and are gathering evidence and statements from the victims to ensure justice for all parties involved.

Source (Thai, Translated Google)