the mayor called it the worst day in the history of the houston fire department. four firefighters killed while responding to a huge hotel and restaurant fire an friday. running into the flames because they thought people were trapped inside. four died when a wall collapsed. the fire chief says other firefighters immediately began digging through the rubble to get to them. the deaths are a sobering reminder of how dangerous this job can be. cnn has more on how the department remembers their fallen comrades. reporter: ann sullivan had just graduated from the fire academy in april. we called her punky because she was named after punky brewster. she was short, cute and small. reporter: she worked as a volunteer firefighter at this station outside of houston before deciding to make it her