Fourth in a series about Costa Mesa's political battle.   He
could have spent his retirement traveling the country with his
wife or volunteering at a museum, but Tom Arnold decided his 30
years as a firefighter weren't enough.  Arnold had retired after
climbing the ranks of the Newport Beach Fire Department. He was
settling into a life of leisure and community service.  Then,
after rising from relative obscurity, he brokered a truce
between the Costa Mesa firefighters and the City Council — two
groups who had bickered publicly for years. There was talk of
the city outsourcing services to the Orange County Fire
Authority, a move municipal firefighters didn't oppose because
of the Fire Authority's more-generous retirement plan and other
factors.  But the council wanted to keep fire services in-house
and signaled a willingness to play ball with the union, sources
familiar with negotiations said.  As the city's interim fire
chief, Arnold crunched data about emergency response times and
convinced both sides his pl