BAC referred to blood alcohol content, the measurement of the alcohol concentration in the blood. In the US, the legal limit on a person's blood alcohol content while driving was .08 percent.
Frank and York were definitely over the limit. It appeared as though Li Du had good intentions, but he had actually set them up.
Some male police officers came forward to pull them away, but they still resisted. Frank pushed the police officer and shouted, "I will comply with the investigation, but first let me find out about our—"
The police officer who was pushed was now angered; American police did not care about civilized enforcement after being assaulted.
Frank's action was considered an assault on the police officer. The officer pulled out his revolver and yelled, "Squat down! Hands on your head! Or I will act with violence!"
York and Frank were now terrified and could only squat down despondently, with their hands on their heads.