Firefighters from five towns extinguished a two-alarm fire on Randolph Street on Wednesday morning near the Route 18 intersection. The residents were not hurt, but a firefighter suffered minor injuries. Chief John M. Nuttall of the Abington Fire Department said the fire at 51 Randolph St. was reported about 11 a.m. The two-alarm blaze ate away at an exterior wall and had begun to burn in the spaces between the house’s walls. “When the fire gets into the void space, it tends to travel,” Nuttall said. “These older homes tend to have a lot of hidden spaces.” By the time firefighters arrived, Nuttall said, the fire was burning between the home’s interior walls. Firefighters broke through some of the walls and ripped into the attic before they were able to put the fire out. Nuttall said he didn’t believe the house was a total loss.