Courts in NC have ruled that police have no obligation to protect you from harm.
In 1988 a man went crazy and started shooting at passing motorists. The local sheriff's dept set up a road block at one point, but continued to direct drivers into the shooting zone from another point, resulting in two deaths, if memory serves.
The families sued, and were told by the court that the police had no "obligation" to actually perform their duties, and could not be held libel for people's death, no matter how negligent they were in the performance of their duty.
Four people died despite repeated calls from family members and friends that Michael Hayes possessed firearms, was threatening to kill people, and was becoming increasingly agitated and violent.
Despite actually discharging a firearm in from of two deputies, neither saw this as a reason to arrest the man.
Later when multiple reports of shots fired at passing cars and reports of people gunned down were phoned in, the Forsythe Co. sheriff's dept decided to respond in force. They set up a road block, then proceeded to direct motorists directly into the kill zone for reasons that remain unexplained to this day.
The courts protected the police from civil responsibility ruling:
The general rule followed in this state is that ordinarily law enforcement agencies and officials are not under a duty to protect individuals from criminal actions of others unless there is a "special relationship" between the injured person and the police or a "special duty" arising because the police have promised protection to a particular individual.
In NC, at least, you may be gunned down in the police station and the police are under no obligation to act tp prevent your death.
http://nc.findacase.com/research/wfrmDocViewer.aspx/xq/fac.19910903_0040407.NC.htm/qx