The case was appealed to the Circuit Court and the trial judge upheld the district court verdict. The defense to the case involved "sovereign immunity". This is the concept that governmental employees are in some instances immune from civil lawsuits for negligent acts committed while in the course of their "governmental" employment.
In this case, the immunity would apply if the officer was "in pursuit" of suspects. The testimony was that the suspects he was pursuing were standing still and consequently the officer was not "in pursuit" or engaged in "emergency service." For more go to: http://www.baltimoresun.com/news/maryland/crime/bs-md-hermann-police-pursuit-20101006,0,346120.story