advertising free admission to the zoo for firefighters and other first responders who "worked heroically to control and extinguish the October fires and support fire victims."
Seems they need help exercising the tigers. They figure guys who fight wild fires can run faster than a tiger, and after what happened in San Francisco, I guess they want to ensure the runners are quick.
As to San Francisco's Christmas incident, here's the quote of the day, from Ron Tilson, conservation director at the Minnesota Zoo and coordinator of the Association of Zoos and Aquarium's Tiger Survival Plan Program, when asked why a tiger had never previously escaped from the 1940s-era grotto replied, "It probably didn't want to."
Pretty much sums it up... perhaps...